Oscillators, amplifiers, light control

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Chapter Two – Some more stuff… oscillators, amplifiers, light control

Who said oscillators aren’t interesting. Considering it’s the very foundation on which all digital electronics is based it must be. Think of the extremely powerful desktop computer, that laptop or tablet – it all begins with a train of pulses called clock-pulses. And how did that all start? With an oscillator of course.

Parallel rod push-pull 120MHz oscillator.
Retrieved October 12, 2014 from W. W. Smith, ed. The Radio Handbook, 5th Ed. published by Radio, Ltd., Los Angeles, 1938, p. 427, fig. 23

And then we have amplifiers. What exactly is an amplifier? An amplifier can be used for many things and strangely enough although we see and hear about audio amplification many people aren’t aware that we have amplifiers for light, microwaves, radio, we even have a thing called a magnetic amplifier. But all amplifiers serve one purpose – to amplify a small signal into a huge or even a ginormous one. LASER – Light Amplification by Stimulated Emission of Radiation. How about MASER – Microwave Amplification by Stimulated Emission.

Why throw in light control into this chapter? Well, all things being equal we do believe that most youngsters starting out in electronics get the biggest kick out building a light flasher. A simple circuit indeed but one which you will never forget. I do believe that one of the first circuits the avid Arduino fan will build is going to be a light flasher. Think of this as being the “Hello World” in programming, something you will never forget.

James Clerk Waxwell — James Clerk Maxwell – Genius Scot

But lighting control can also be synonymous with high powered audio – you can build light chasers and sound to light circuits (can be very dangerous of course because you will be working with mains voltages) but what about lighting control of the more sophisticated kind. This would be DMX512, digital multiplex controlling of lights used in theaters, live band performances and yes, your own personal disco.

But first let’s go to the beginning again…

Oscillators – in electronics of course this would be a device which is non-mechanical producing a continuous wave of some sort. There are some that don’t even do this, they only produce a short ringing tone diminishing in amplitude.

No electronics guru on this planet will be worth his or her salt if they did not know at least the following five types of oscillators, so thanks to Jimmy Wales we need look no further:

Crystal
Colpitts
Hartley – notice the similarity with Mr. Colpitts?
RC Phase Shift – many students love RC Phase shifters and #5.
Wien Bridge – this is usually a difficult one to learn but a great learning tool.

Just before you get bored to tears please understand one thing of really great importance – if you plan to build radio receivers or broadcast transmitters you will need to know a “lot” about oscillators. In fact, almost every Amateur Ham has built at least one oscillator in their lifetime. Read up on our “The VCO or Voltage Controlled Oscillator“, one of the fundamental and vital stages used in “effects” music or synthesisers.

Chapter Three: Audio amplifiers

Chapter One: Beginning the Sequence

[Ed’s note: Much of what we study in modern day electronics goes back centuries. Chemistry played a vital role in much of their experimentation. There were many brilliant minds hundreds of years ago, Nikola Tesla (featured image) and James Maxwell being just two of them – do read up on their works. Much of the theory was very advanced, even by today’s standards and even the more astute of us will find their work intriguing but yet difficult to understand]