Line Voltage Regulators

[CAUTION: This article is in response to a reader’s mail. It’s a guideline – there many ways to skin a cat. We do not have nine lives – take caution. We will not be held responsible for incorrect wiring, circuitry and/or modifications that our readers carry out themselves. Always consult an electrician. It is highly illegal to tamper with wiring connected to your supplier. Electrical code is there for a purpose- read it, understand it, be responsible].

As a result of a previous article “Power Inverters – The Real Thing” we had a reader drop us a mail on how he managed to reduce spikes and line transients from the genset by using a UPS and line regulator connected to the UPS output.  This should never be done. The surge protection device, if it is a movistor, will damage the UPS. Connect the surge protection before the UPS. Not all UPS have very sophisticated input protection circuitry – focus on the source and not the output.

Never connect an inverter or UPS back on to the mains supply – read up on back feed or islanding. A UPS is not designed to be looped – i.e. output to input and remember non-grid tied systems do require a transfer switch.

For generators, use an online UPS. Line interactive UPS don’t always like generator power.  (neither that from inverters). Often very small gensets do not have a very good AVR and output voltages swing wildly through the recommended safe operating voltage of an electronic load. In some cases it is desirable to use a step down transformer, rectifier and smoothing circuit feeding a SMPSU e.g. 9~15 with a DC 12V 20A output. (look at the SD range from Meanwell with 19 to 36V DC input). It is far easier to control a low voltage than an output voltage possibly exceeding 300V. (this is for low power equipment used for camping possibly). There are many permutations to this trick but like all roads lead to Rome – always check your output voltage before connecting a load. Large diesel gensets are usually rock steady and most UPS types can be used comfortably. A very useful piece of equipment is a self made genset using a 4HP lawnmower engine driving an automobile alternator for 12V battery charging.

DIYers the world over are learning to adapt technology to suit their needs using solar and wind power. To live entirely off the grid is the goal of all.


Power Inverters – the real thing

Inverters used in UPS


Inverters and UPS

Buck, boost, invert, batteries and PWM – where does all this fit in?

[Editor’s note – this article covers the emphasis of the use of inverter circuitry inside UPS systems. There are many different types of UPS systems available in the market, some only powered by a battery and relay, others by electronic switching, regulators, inverters and power factor correction. We find the APC website (we are not affiliated to them neither do they endorse this website 😀 ) full of invaluable information for anyone wishing to invest in a UPS, whether large or small].

There has been a lot of galloping to the stores of late as Chinese inverters are making their mark for back up power to the home – they are priced well, reliable and just about anybody can install them. There are some pitfalls though. We won’t go into the heady details of R.M.S. power or how to design PWM/chopper circuits.

1) A UPS has an inverter stage.

Inverters used in UPS
Line Interactive UPS Explanation: Wiki Commons – DMahalko, Dale Mahalko, Gilman, WI, USA

Inverters and UPS both use similar technology, transistors which are driven by a square wave to switch (chop) a DC supply through a transformer to get a square wave output but average out to sine at country supply voltage (or designed equipment supply) or a pure sine wave inverter which may be driven by a 50Hz oscillator, sine wave. A UPS will detect low mains incoming voltage and boost it or on high input voltage will reduce (buck) the output supply. Both the inverter and UPS will always try to give as close as possible to an output sine wave as can be designed. Whilst a pure sine wave is desirable, they are very expensive, generate a lot of heat and are very heavy. Modified square wave (standard UPS) is great for computer switching supplies but not for inductive loads e.g. your amplifier mains transformer. Inverters however are often more designed around trying to drive inductive loads like fridge compressor motors, swimming pool pump motors and drilling machines. They were not before because of the high cost – Insulated Gate Bipolar Transistors (IGBT) have changed this in many ways.

2) An inverter may not have a buck/boost circuit.

3) A UPS which boosts and bucks is called a line interactive UPS and is the most popular amongst computer users. They are also cheap and reliable.


Inverters driving UPS, PWM, bucking and boosting

Both the UPS and the inverter use PWM or pulse width modulation, sometimes. Cheaper inverter units are free running (meaning oscillate freely at a designed fundamental frequency).  They may not have a feedback circuit or current sensing. A UPS used for backup supply for a computer or server is rarely free running and do have a lot of fail safe circuits built in.

4) Many cheap low power inverters are free running or set to a fixed frequency without PWM

A UPS can be driven from an inverter, meaning the inverter feeds the UPS. The UPS will then be used to clean up the inverter output voltage. A standard inverter needs a battery supply to run. But then again so does a UPS if there is no mains power. Confused?  The only thing we now see (in some circuits) is that an inverter does not have a buck/boost control. Sometimes we read about the switchover period in milliseconds as the inverter switches to battery. Well, the same applies to a UPS, both hybrid online, double conversion and offline. The online (double conversion) UPS has a very beefy DC charging circuit which when detecting a low or high input will automatically regulate the output without switching to battery, whilst with an off line UPS one can hear the switching and beeping taking place to warn the user that it is switching between mains supply and battery. On line UPS usually transfer to bypass when the load varies significantly. Confused now?

5) An online UPS will have a transfer switch, often utilising silicon controlled rectifiers (SCRs) to bypass the DC and battery charger circuit under heavy loading.

With the online UPS the battery does not get used when bucking or boosting which places less drain on the battery. The off-line UPS can be quite dangerous here because the user does not know the battery has been drained until the system shuts down. An inverter of course runs all the time off batteries. Ummm…

Or so we thought.


In fact all three topologies are made to run directly off batteries when there is no mains supply – much of what we read is not entirely true, possibly hype and of course economy of scale play a role. A UPS is an inverter circuit. It does run off a battery. There is in most cases a changeover relay. If one had to design an inverter circuit which ran off the batteries all the time but at the same time the batteries were being charged we would in theory have an online double conversion UPS. UPS means Uninterruptible Power Supply. A battery which is being charged while mains power is available and it feeds your household lights is therefore a UPS. There should be no confusion here. Many systems engineers believe the best UPS to have is in fact the line interactive variety because there is less stress, no bulky power supply, no excess loading of small generators, less heat, less cost.  And they also the cheapest to manufacture, even cheaper than an inverter. Strange!

Does your UPS kill spikes and surges?

Many UPS have very primitive voltage spike suppression circuits – in fact all it needs is a Movistor or Metal Oxide Varistor. This component prevents mains surges and/or transient spikes getting through to other electronic circuits causing damage. They are usually placed at the mains input. They come in a variety of sizes, voltage clamping and energy ratings. They are dirt cheap. Then we have the line regulator or stabiliser circuit like the APC -L-R1200. This unit is not an interruptible power supply (no batteries, no inverter) but it does protect your sensitive equipment during brownouts, surges and spikes using a transformer with multiple taps.

6) A UPS may be damaged by a voltage spike.

APC inverters or online or offline UPS

No, not all UPS are built the same. APC (now under Schneider) have long made UPS which are deemed very reliable. Although costing more than many imports they offer better warranty terms than most other UPS manufacturers. This does not mean the others are bad in case you are wondering. Always buy a reputed make or through a reputed supplier.

The expense of batteries

Whilst most UPS are very reliable the batteries may not be. Most users turf their UPS when the batteries fail because either they are not aware that the battery has lost it’s mojo or the replacement price is exorbitant. Always replace with a known good battery and yes, again, the manufacturer or brand name is important.

7) Your UPS is only as good as the battery.

Inverters are for big power, UPS for small power

Another myth is that an inverter can supply many kW of power whilst a UPS is limited to a few kVA. This is not true – APC even have a UPS which delivers 40kVA 3 phase. (and more if you want). When running very high powers the battery supply is usually series connected, sometimes 240V (20 12V batteries in series).  The problem is when a high powered UPS is designed to run off one 12V battery or possibly even two the currents are huge and just not practical. For instance a 2kVA UPS could be made to run off one 12V battery but the current would be in excess of 200A. At 24V this would amount to 100A and of course, 48V, 50A, which is more design friendly. If you are attempting to fire up your own design, never start big. Big current means big fire. UPS design engineers are very clever people – safety is always their first concern.

8) A UPS can be designed to deliver as many kVA as an inverter. It is an inverter.

Bigger is not always better!

There are a number of 5kVA designs on the internet which may or may not appeal to the novice. My advice is to stick to what works – a UPS for the PC, A UPS for the television receiver and satellite decoder/receiver and a dedicated light circuit coupled to an inverter. If one goes, the whole lot does not go. Any fixed wiring from inverters to household circuits must be done by en electrician. The inverter has to be certified by your local power authority or through a local bureau of standards, not the one in outer Mongolia. Your home brewed inverter will not be covered by insurance, neither the damage to your house or apartment in the event of a fire. Poorly installed down lights are often the cause of fire, likewise your vampire sucking mini-supplies used for modem/routers and cell phones.  (Ever seen a small PSU, usually cell phone charger, plugged in at the mains with a curtain hanging over it?).

9) It’s cheaper and safer to buy unless you are a design engineer.

A 5kVA inverter should be run of a minimum of 48V with a current capacity of 100A/Hr. Better still, 48V in parallel – at full load you are only looking at a maximum of 2 hours usage. Use solar panels for charging by all means but never forget the tried and trusted genset. It’s no use having the world’s best inverter when the batteries are flat and there’s no sun.

Inverters are connected to big battery supplies, UPS to small, internally mounted.

Not so, many manufactures allow extended run time batteries to be connected.

10) Many UPS can take extra batteries to extend run time. You can also modify – take heed of warranty and charging circuit.

To conclude…

Whilst many engineers may cast suspicion over what has been written here I can promise the layman that I have worked on many inverters and UPS circuits. I do find switchover relays in online UPS and APC do commission their high powered UPS to ensure installation is 100%. To prevent confusion do think of an inverter circuit forming part of a UPS and not a separate entity entirely. I often do advise users to rather use more than one UPS than many unless they are installing a dedicated circuit to their house which is to be powered by an inverter and many deep cycle batteries. Or a bunch of programmers needing a dedicated UPS on a generator for backup.



Stereo Systems vs Multi Channel

Stero Amplifiers - the original Crown DC300A


Why do we still want stereo systems?

Recently an elderly reader sent a personal email to us complaining about all the parasites chasing him at the AV stores trying to sell him a 7.1 sound system when all he wants is good quality stereo.  Well here’s the good news – he’s not alone. For pure movie extremists, stereo will not cut it. For excellent music reproduction 5.1 to 400.1 systems sound, well, more often than not mediocre. More often than not the smaller surround speakers serve no purpose at all – one might hear artificial clapping or soft vocals but the reality is, listening to any live show the music is from the front. Stereo systems also have separate tone controls – who wants to hear music as if it’s played through a tin can?


Try as I might, playing a movie like Die Hard has to be heard through a multi-channel system. Stereo just lacks depth for certain movies. As an all rounder though most music and movie buffs seem to stick to stereo. The movie even has an optional stereo out. The problem is, unlike 3D, multi-channel receivers are not going to go away. They are getting better even though a lot of what is thrown at the buyer may appear to be gimmicky. In the late 1980s through the 90s there war taking place as to which line system satellite broadcasts would incorporate. This is still a problem, HD, Blu-Ray, 2K, 4K, 8K etc, etc. Technology does not move as fast as the hype. Curved screens are topping the list but at what point should we be saying enough is enough. Are sound bars as good as the hype? Do we have the space for a 9.1 sound system?

Stereo Systems - the original Crown DC300
Stereo Amplifiers 300W into 4 Ohm Manufacturer Crown – wiki commons Binksternet

Stereo Systems vs multi channel sound bars

In the good old days the sound gurus were pedantic about speaker placement. This was to stop unnecessary reflections and get the right sound image. Actually the perfect sound image. How many audiophiles are buying soundbars? If one uses near field reference monitors there must be no reflection, no external vibration and no sonic resonances. The recording artist or engineer wants to hear reproduction without colouring. ‘Hi-Fi’ speakers add the colour. Placing a sound bar by your TV stops clutter, how good is the quality though?

Beginning of 2015 a search into audio advancement returns that wireless coupled speakers are the next big thing. Wi-Fi has been with us for some time. Playing your iPod or S4, 5 or 6 through NFC or wi-fi cuts out a lot of wiring but for home theaters? Each speaker needs it’s own power supply still. Why aren’t we using the mains circuit to transfer the audio? At line levels and with modern technology this can easily be done.  20Hz-20kHz is a very tiny bandwidth. Cost and multi-plug adapters can be a problem. Wi-Fi is cheap and a lot more R&D has gone into wireless – but don’t rule out the pre-existing mains wiring.  Wi-Fi rules for sound bars and multi-channels but not a wired stereo amplifier.

Stereo systems don’t need processors

Most entry to mid-level multi-channel systems have an ‘intelligent’ processor system to generate the surround sound but when it comes to stock standard high quality SACD reproduction something is lost in the audio chain – typically the lack of separate bass and treble controls. I’d like to think that the problem is in the processing, the digital factor.  Modern movies, CGI, effects all require great audio through a 5.1, 7.1 or 9.1 receiver. Music is unfortunately strictly analogeous, from the sound of a violin, bass drum to the vocals. The less circuitry in-between the better so you do not need a processor.  A case in point would be comparing a class AB amplifier to class D. Class D is just great for driving bass bins, they are lightweight and comparatively cheap – the mid to highs seem to be lost in the filtering process but they are getting better.  Class D lends itself perfectly to the digital processor.


HDMI – another communication channel

A good multi-channel receiver has more than just one or two HDMI sockets. This is good if you like HDMI (or HDMI 2.0) – is this standard going to be with us for always? If the lifespan of your receiver is going to top 5 years then this is the way to go.  Throw in Bluetooth and Wi-Fi. If you have lots of money to spare, think about getting only a processor. Feed the amplifiers from the processor. Interestingly enough a processor costs more than a receiver which has possibly 7 audio amplifiers, one LFE output and multiple processors in one box. People say it’s because the processor is usually very good quality. Others say it’s economies of scale. I say (because I have done it) buy a known good receiver which has audio power limitations (2nd hand for 100 dollars), get the schematic and take the signal from each pre-amplifier.  This means you will have the processor at your disposal and you can modify it to take a phono input, add in bass, treble, balance if you want. It’s all yours. (If you need to know more about this, drop me a line to

In my opinion the best of both worlds can be had by connecting the good quality L & R front loudspeakers through a switch-box to a stereo amplifier and the multi-channel receiver. I don’t like this idea though unless you can limit amplifier output when switching between amplifiers.

Another thing, most A/V amplifiers, although rated at a specific power per channel and where the manufacturer has not polished up the specifications a tad, will have limited power handling on all channels driven simultaneously because of power supply and cooling limitations. A/V amplifiers are often prone to transformer protection failure and transistors blowing because of being either driven to hard continuously or incorrect speaker loads been applied.  And in most cases music is the culprit. A 700W continuous rated unit will have a power supply costing in the region of 200 dollars. Feel the weight of a typical A/V amplifier compared to a Crown 500W R.M.S. unit. (not with switched mode power supply though).

The wire-cutter has a great article “The Best Receiver“. Read it and digest.

Both A/V multichannel amplifiers as well as stereo systems have their place. Rage on, a good two channel system with good quality loudspeakers is still king..




The Power of Two

Power - the Safe Operating Area


Power Amplifier Kits

For builders of electronic audio kits there is a plethora of stock been advertised either from the East or Europe. Whilst I am sure many of these kits are good quality, with a few exceptions, buyers should be cautious of the overzealous power ratings advertised. A case in point would be the ‘rugged’ design using a very popular TO3 NPN transistor, the 2N3055.  Compared to modern devices these transistors are still very popular and with careful design can give quite a remarkable sound quality but there are limitations as to what power you can get safely by using only two transistors in a quasi complementary output. This not unlike any other output stage of course but the ratings I have seen advertised go way beyond the norm. Four transistors used in the output stage used to produce about 125W R.M.S. into a 4 Ohm load at 80V (taking supply droop into account). Regulating that supply to 80V DC you are looking at (((80/2 * 0.707)/4) * ((80/2 * 0.707)/4)) * 4, a theoretical output of 200W R.M.S. The formula used is just a play on Ohm’s Law to get Power or I*I*R in R.M.S. value. Four output transistors in a quasi-complementary output stage should suffice, but err on the side of caution and add an additional pair. The amplifiers I have seen advertised can nowhere dissipate that type of power with only two transistors in an output stage, driven in bridge mode into a 4 Ohm load. Design engineers and manufacturers always resort to the transistor specification and the Safe Operating Area or SOA. This will always be given – if not, then do not use the transistor. Of course, stay clear from counterfeits as well, they never do what they are supposed to. As they say, there is nothing like a free lunch, especially when it comes to peace of mind. Good quality transistors are expensive.

Power - the Safe Operating Area
BDV66C SOA – Wiki:- Sönke Kraft aka Arnulf zu Linden

R.M.S. or Root Mean Square

R.M.S. power is significant here because all good amplifiers are measured in R.M.S. right? Not really. R.M.S. is merely an alternating current circuit’s equivalent direct current heating capability. In other words, an alternating current circuit with an output measured at 40V peak on the positive going waveform is 0.707 * peak or 28V equivalent D.C. voltage aross a 4 Ohm load (pure resistance, no inductive or capacitive loading) and using Ohm’s Law we get to current V/I or 28/4 = 7A.  Power dissipation into this 4 Ohm load is calculated via means of I * I * R or 7 * 7 * 4 = about 200 Watts.


R.M.S. is therefore not Real Mean Sound neither Real Media Sound – it’s a term we love to throw around, that’s all. When measuring amplifier output we also need to know how much distortion is been delivered as well and of course at what frequency. Loudspeakers are really inefficient little blighters. The voice coil is inductive, there is also capacity. In an inductive load current drops as the frequency is raised whilst in the capacitor, the reverse is true. In theory the ideal amplifier output is measured without any distortion at a fixed and common frequency, say 1kHz into a pure resistance of say 8 Ohm. If we do not know what the exact resistance (in a.c. circles we call this impedance) of the loudspeaker at 1 kHz how do we know that the amplifier is in actual fact dissipating the power calculated by measuring the amplitude of the waveform with an oscilloscope and assuming the ‘resistance’ of the loudspeaker is 8 Ohms. So we can safely assume that with a pure resistance of 4 Ohms and measuring the amplitude which may be 40V peak or 28V R.M.S. we have 200W dissipation.  A quick methode to calculate what the amplifier ‘could’ put out in terms of power is Vcc squared divide by 8 x load resistance.  Therefore if the amplifier supply rails are +40V – 0 – -40V and the load is 4 Ohms = (80 * 80) / 32 = 200W.

Don’t burn your Bridges

Now what happens if we decide to bridge the amplifier. We need two audio amplifiers, the inputs driven 180 degrees out of phase with each other. Sound simple? It is. The problem now is dissipation because we really don’t double the output dissipation because we have two amplifiers feeding one load. In fact if the previous amplitude was 28V R.M.S, this is doubled but not the output dissipation. No, the 56V R.M.S. across a 4 Ohm load means we have V/I or 14A pushed through and in terms of output dissipation, 14 * 14 * 4 or 800W, four times the amplifier rating. If an amplifier is designed to dissipate 200W into a 4 Ohm load, in bridge mode it will tested with an 8 Ohm load, not 4 Ohms.  Into 8 Ohms we dissipate 400W, double of the amplifier rating into 4 Ohms.  Often modern amplifiers are designed to dissipate large quantities of power into 2 Ohms but on bridging they are designed for a 4 Ohm load.

An amplifier which is designed to drive a 4 Ohm load where the output stage is running just within spec will be damaged if bridged and driving a 4 Ohm load.  For that reason rather not bridge and never use a lower impedance that that intended.

Tube and some class D amplifiers on the other hand should never be run without a load.  More on this some other time.

Before buying your first or next amplifier kit be sure to know how they did the calculations.  The supply rail voltage and transformer VA rating is always a good indication of what power to expect – knowing the specification of the output transistors is sometimes more important.

Read: Safe Operating Area – Wiki




The Internet of Things

The Internet of Things


The Internet or Nothing

Is IoT another load of hype coming your way? Do you talk to your toaster?

An interesting fact about the web over the last 20 years has been how it has grown to be the single most used tool along with the laptop, home computer or Smart Phone next to a light switch or a TV remote control.  Just Google “Is the Internet making us Stupid?”

I for one get up early every week-end to catch the news and surf the web. Not that long ago we had newspapers delivered to our door. When we need something looked up we no longer go to the library and take out a book, Google is there at our fingertips. When we have a medical problem we look it up on Google. Car problem? Alien vegetation? Google is our friend. Thanks to the Internet!

The Internet of Things
Copyright – Christopher B. Wright

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 4.0 License.

Many years ago…

Now go back forty years. You leave school, you do not do an aptitude test – you go to where you think you want to be, maybe a bank, armed forces, study English, split the atom or become an artisan. All your notes are already in Portable Document Format i.e. in hard print. You become an artisan, you become an electrician, a plumber or welder. You become a mechanic, boilermaker, sheet-metal worker, fitter & turner or electronics technician. All of these jobs require either an academic or practical approach.  The internet made things easier if you took an academic approach but, the emphasis on but – don’t trust everything you read. Books were more reliable to get information from, you know the author and his or her credibility. On a practical level you need to weld or cut, fit, turn, mill and test.  A book can show you but the best artisans are those that fit the trade and have experience. (meaning have the aptitude – there aren’t many lawyers that make good motor mechanics, neither fitter & turners making good accountants).


The internet made some of our jobs easier. Reading is never a substitute for doing. You’ll get lots of advice on the web about milling, repairing motor car engines and installing geysers. Most of it by people that have never done it in the first place. We can get legal information easily on the net, some it may make sense, some of it not. Try to learn to weld through the thousands of returned search results and you’ll be surprised by the results.

Making sense of the Jungle

All the theory can be obtained on the internet if you know where to start. Like most courses which direct the learner – in electronics you do not start with the magnetron, you start with thermionic tubes. You also start with Ohm’s Law before resistor colour codes and then of course you go on to thermionic emission, germanium and silicon diodes and bipolar transistors.  Trouble-shooting is more or less in the same order. This is where things start going wrong, losing pieces to the puzzle.  The Internet can be a jungle.

The best artisans are those that trained through family – a genetic hand me down (passion and raw talent), those that trained in a real live workshop and lots of theory to become qualified – this means hundreds of hours at the lathe, welder, milling machine, but very seldom the through the pages on the web. Is this changing?

Machines and Robots

CNC (Computer Numeric Code) machines and 3D printers are not new, in fact the first CNC machine was designed and built over 50 years back (NC or Numeric Controlled). The fact that our desktop computer made things easier, the serial port controlling a batch of stepper motors through their relevant drivers made this a stepping stone for already qualified machinists. The fact that this in turn lead to the first 3D printer in the early 1980s meant historians need to start revising their theories on the Industrial Revolution which in our case did not exist through the the 1800s but rather from about 1800 to present and still continuing. Machines keep on making us humans obsolete until something goes wrong.  Aren’t machinists and electricians the best people to have around when a machine goes wrong? When your ADSL connection goes haywire will your microwave self destruct? Do we now need computer technicians to fix our fridge or milling machine?

The Internet of Things (IoT)

If all objects were networked enabled and could communicate with each other are we taking another step forward in the field of robotics and artificial intelligence?  Or is IoT just an add on to the internet, like social media? Possibly. A typical example would be motor car engines fine tuned 3 000 miles away at the factory.  Definitely not ground breaking stuff! We are after all using technology as in it’s present form but through proper intelligence.  Home automation? Even with the most sophisticated security systems at our disposal the common and garden criminal finds his way into the modern home by using whatever devious means they have. We rely on electricity, power and wireless or cable, all known to have weaknesses. The more we interconnect and become reliant on other devices the less reliable it really is. The Internet of Things may seem like a great vision but maybe it’s been with us for some time already. Possibly when Samuel Morse was born, or Marconi.

Coming Back to Planet Earth

Professor Leonard Kleinrock published “Information Flow in Large Communication Nets” in 1961. So we had the idea then already. Remember that scientists from Morse’s day already were trying to speed up data flow – who wants to learn Morse code if you can speed-dial your partner through a cellular network? Evolution. Packet exchange, TCP, DNS, IP, modems, switches and routers.


The interesting aspect to this whole saga is that the good Professor already had a grasp of what he wanted to do, nothing different – just a name.

The sad reality is that data exchange has been around for years and many people believe that IoT is going to change a lot of how we do things currently – it won’t because it’s here already. IoT is a wonderful abbreviation, another piece of technical jargon we can throw around at parties and impress our friends. I just don’t get it though. Tim Berners-Lee was the guy that cracked the www code and made the way in which we communicate so much easier. Communicating with our router is also IoT. So is handshaking and duplex working with morse code.

Another catchphrase?

Please change the name to something which doesn’t sound so much like a Geek catchphrase but one which is meaningful and leans on the TCP/IP protocl. NFC is another cloaked Geek speak. Do you know that many electric toothbrushes work through a NFC to charge the battery. So does an induction motor.

I don’t use the internet to communicate with my Weber or Cadac. Neither should you. Ban IoT get a life!





Honda CBX 1000

Honda CBX 1000


A collector’s bike -the Honda CBX 1000

Like the first landing on the moon, the Honda CBX 1000 was as exciting and as intimidating. Sharing the road test in a local newspaper as a picture of Britt Ekland (I think it was 1978, my first big screen actress crush), both looked just so absolutely awesome. The CBX had it’s fair share of problems, stated mainly by the jealous masses whom admired but could not afford and those that were just downright anti-Honda. Nowadays this bike is a collector’s favourite, it is affordable and it still sounds better than most machines on the road. Now if only Honda could bring out this bike again with fuel-injection.

Honda CBX 1000
Honda CBX 1000
(Andrés Teixidó – Honda CBX 1000 del año 1978. Imagen tomada en Buenos Aires, Argentina)

I first rode a CBX 1000 in 1982 when my mate told me that his bike needed a service, could not get to 136 mph. Of course I took the bike in for a service but don’t ask me to do 136 mph afterwards, which he asked of me. He gave me the thumbs-up a short while after – he got the magical 136 mph. I don’t know how because the wind was against him, we know also that speedos don’t lie. This bike was really incredible though. It felt as if you were in a sportscar, as comfortable as a modern day SUV but with just lots more power.  Compared to a modern day 600cc superbike though it would not stand a chance. I believe this bike weighed about 300kg, this is obviously always going to be a problem. Once up and going the bike didn’t feel cumbersome though, far from it. I have never ridden a Kwacker 1300cc though, I can’t imagine picking that machine up after a slip. The Honda already just looked too big. However….


Chasing through some articles on the web recently I came across a project which I just had to show our readers – a CBX V12 built by Andreas Georgeades, published on The Kneeslider website.

Catch the video here:–zY


Electronic circuits – projects listing

Circuits - measure current through the Ampere Meter


AF, Video Amplifiers, Timers, Light Control, Arduino, Raspberry Pi Circuits

Rediscover electronics as a hobby and link to this page for every circuit known to mankind. Unfortunately as we all know, links come and go, pages may become obsolete or links inactive without us having the time to amend. Also, most of these circuits have not been checked by us so we cannot be held responsible for their accuracy, working or your own safety. Never work on mains powered devices as a first project and always make sure you have an isolation transformer or GFIC (Ground Fault Interrupter Circuit) as added protection. As first projects go the safest is run from a PP3 (9V) battery or through a transformed regulated supply with current limiting. Do not attempt circuits which use thermionic tubes or valves as they require a substantial anode supply to be effective (upwards of 300V DC).

Circuits - measure current through the Ampere Meter
“Amperemeter hg” by Hannes Grobe (talk) – own work, Schulhistorische Sammlung Bremerhaven. Licensed under CC BY 3.0 via Wikimedia Commons –

A listing of other listings or the pages have been built and tested by the author.



These are just some of the better websites on the web. Yes, I did Google it and yes I have browsed through the relevant pages.  ESP remains one of the best (my opinion) in terms of explanation and accuracy.  For another one, if you are an audiohead:

Nelson Pass DIY – well put together website which gives readers more insight into circuit design.


As most DIYers will recall, their first circuits may have been around audio or RF, possibly light flashers and buzzers. No matter which circuit you build or direction you take, think Voltaire, Ohm and Ampère, the pioneers of this exciting hobby (or profession). Students of electronics in the 1970s may possibly have had the best of both worlds, tubes (valves) and semiconductors. Semiconductors paved the way to microelectronics. Digital electronics is now an everyday part of our life but analog is just as important. Our senses are analog in that they can measure varying degrees of sound, touch, light etc.  Combining the two we build very sophisticated circuits, control our world.



Workshop Tools – try these at home!

Tools - Woodworking Tools


Tools – what to buy?

Tooltime Adendorff
Adendorff – South Africa

Having worked both at home and professionally with spanners, screwdrivers, drilling machines, milling machines and lathes all my life there is no greater emphasis on you get what you pay for.  I won’t go into detail as to which brands to veer away from – there’s literally thousands, but do be cautioned.

Tools - Woodworking Tools
Tools – Woodworking Tool Brands – Woodsworking Plan


Sockets and spanners, ring and flat, screw drivers, pliers and general tool sets: 

  • Stahlwille – German
  • Snap-On – USA
  • Repco – Australian
  • Gedore – German
  • Wera – German

As a general rule, German and American manufacturers are exceptional. It’s not unusual to find tools made at the turn of the last century still in existence and being used daily. The Australians are also in this list, besides Repco being one of the biggest suppliers of aftermarket parts, they are also extremely tough.

Cordless power tools and some not so cordless:

  • Milwaukee
  • Bosch
  • Makita
  • Dewalt
  • Ridgid
  • Chicago Electric
  • Black & Decker
  • Metabo

The Milwaukee brand,  a subsiduary of Techtronic (also Ryobi and AEG) has fast been recognised as been ‘possibly’ the star of the show. Most professionals use Makita, Milwaukee, Bosch and Dewalt. Although Bosch may be the name most of us know, we also have Skil, Hitachi, Craftsman Nextec, Porter Cable and Rockwell (Lithium Tech).

Why Black & Decker? All of the above are good, for non professional use I have a Black & Decker CD14C and a Ryobi CD18. The Black and Decker must be about 8 years old now and the battery is still fine. The Ryobi lasted 2 years. (Ryobi do make fairly good entry level gear – their electric saws for quick cuts are marvelous for their price). I have seen Black & Decker 220V drilling machines still running after more than thirty years of service.


Mains Power

Ummm, here’s a good one:  Wolf Power Tools, a British owned company. I see Wolfcraft and RalliWolf but the original was in Hanger Lane, London – see the post by Gerhard Schreurs from Nederland in Woodworkforums. Interesting read – my dad had a silver grey unit which went missing or the commutator wore out. This was still working in 1995 – so must have been about 30 years old by then. An interesting aspect to taking a journey through the tools currently available on the market is that they have been around for many decades.  Many of these companies are possibly a century old already, Black & Decker being one of them. I doubt there is not a craftsman on this planet whom hasn’t owned either a Black & Decker or a Bosch.

This is not an easy one to list because most of these companies are manufacturers of cordless tools as well.  However, looking at table saws as well as drilling machines.

  • Metabo
  • Dewalt
  • Bosch
  • Makita
  • Triton

I have purchased and used Triton sanders and electric saws and they are exceptionally well made. They are also not cheap. A professional carpenter felt that the Triton Workcentre 2000 was a toy until he actually used one. (yes, the workcentre may not be as exacting in performance for the DIYer as a contractor Dewalt but it’s a breeze to move around).  It is recommended that the Triton 2000W TSA001 be used on the workcentre for better accuracy. Don’t ask me why I know. Mobile units are prone to sloppiness which a casual user will have problems with – if you know the saw limitations and are a professional user much of this can be overcome by compensation).


Pint sized engineering at it’s best. Cutting, polishing and grinding the Dremel is King! For small jobs. Their add on kit is also amazing, I use the router table, coping saw and drill press. There are limitations however, your imagination and brute power. The Dremel is a must-have for every DIYer, modelist and electronics buff.

Milling and Lathes

This is unfortunately out of the scope of this article but may be touched on in due course. I am not a machinist – in most cases, high accuracy, you need spades of this here, is governed by cost. These tools CAN cost upwards of $100 000.00 for industrial use so be warned. A home tinker may be inclined to build his own however, using CNC. Romanblack shows some great photos of commercial and home built Milling units.


The OBDII Test – not the Messiah



OBDII Test – First tier diagnostics

Intriguing to read about all the hype regarding onoard diagnostic testers and wondered how it went this way. One thing is for sure, the OBDII tester in the hands of an incompetent mechanic can do more harm than good.  It cost me $4 000.00 after a nugget of ingenuity, the chairman of The Global Brain’s Trust misdiagnosed a stretched cam chain through some code or other  pulled out of a hat. That cost $1 200.00 – then came the 6 pints of oil used over 30 miles and a damaged catalytic converter. Engine rebuild, a further $2 800.00. What the hell happened up to this point I’ll never know but forgive I’m not – they were the official agents. So lesson learnt.

OBDII Test - the Auto Boss V.30
Auto Boss V.30 – wiki commons credit Florian Schäffer –

OBDII Test vs the Litmus Test

First of all the engine diagnostics tool better known as the OBDII scanner or CANOBDII, is not the only be all and end all of tools to have in your workshop. Sure, it makes life easier but it’s not the Messiah. Think of it as being a simple litmus test i.e. it can give you a general idea as to whether it’s OK. A better analogy would be the oscilloscope used in fault-finding or navigating by dead reckoning. If you don’t know what the wave shape is supposed to look like or your position is estimated you won’t know if it’s correct or not. Seasoned technicians usually have an idea as to what it should like, for instance the output of a Schmitt trigger, but if there is a glitch, is this normal or not? Yes, I have worked on a radar system which had a very strange looking pulse shape in the display circuit – without the manual I may thought it was abnormal. It wasn’t. (DR has been used for centuries, it doesn’t always have to be scientific though).



Diagnostics testers can have the user running around in circles. A student friend (accounting) purchased a $40.00 unit to diagnose a poorly running engine – after four hours he gave up. The workshop charged him $60.00 to rejoin a loose wire. This took them 30 minutes. Auto technicians usually have a good grasp of the data bus in a motor vehicle – they did after all study this. Most mechanics do not and to make matters worse, management let them loose with a scanner in your car. These testers are therefore only valuable to someone that knows what the OBD system is, what the codes mean and where the fault could exist, which still means a multitude of things.

OBDII Test – know your emissions.

The check engine lamp or malfunction indicator lamp is a bastion of the great USA’s auto manufacturing industry and the fight to lower emission. If the lamp is on or intermittently on it really tells you nothing except that there is a problem ‘somewhere’. This concept kicked in about three decades back and it still remains your number one friend, or foe. The OBD I and OBD II tests may show you that you have a misfire but not the component or loose wire causing the misfire. An interesting point here is that all cars have their quirks.  The old die-hards can trouble-shoot within minutes and remedy the situation. If you do not have the experience this is going to take many times longer. Google can be great for the lay-man but once it comes down to getting your hands dirty, this is another story entirely. On another note, many technically minded kids these days can set up and read diagnostic charts much faster than a 60 year old but the 60 year old will always outperform based on patience. We live in a ‘quick-fix’ world but for an internal combustion engine, there are usually no quick fixes. This means the diagnostics checker is only as good as it’s user. It may only cost 40 dollars, it may show you have a problem, highlighted by a trouble-code but what then?

Many years back a client popped into a motor mechanic friend’s home. He was driving his son’s car (normal aspiration- carb, no OBDII test needed) which was misfiring badly and could not idle.  The mechanic cross-wired the ignition leads – don’t try this at home. It cleared the carburetor of any gunk within a few seconds. Now this is something which most of us may not of thought of and it can be downright dangerous (think flame) but it worked. An old hand knowing his job.  No diagnostics tester will tell you what to do. And that’s the point.

The OBDII test is therefore not the Messiah, just a great and efficient way to put you on the right path. Like the analogy using the oscilloscope, it may have an output – what now?