My DIY Function Generator.

[DrNomis_44]

Hey Everyone,

Thought I would start a new thread about a piece of test equipment I built last year, based on a webpage article I found on the internet, so, what's the piece of test equipment and what does it do, I hear you ask?

It's a Function Generator, it puts-out a steady signal with a frequency-range of about 1Hz, or one cycle-per-second to about 1MHz, or one million cycles-per-second, and you can select one of three different signal waveforms, either Square, Triangle, or Sine.

Okay, so why do I think it's a pretty handy thing to have when it comes to building guitar amps?, the answer is pretty simple, since the frequency range of the Function Generator is from 1Hz to 1MHZ, that easily covers the full audio spectrum which is typically quoted as being from about 20Hz to 20kHz, or 20 cycles-per-second to 20,000 cycles-per-second, and this makes it very useful as a test-signal generator while you're performing setup-tests on your newly built guitar amplifier, or if you have to go back and troubleshoot it if it appears to be not working as it should, of course you could use your guitar as a signal-source if you wanted to, but let's face-it having to pick up your guitar, pluck a string, put the guitar down, and pick up your scope probe can get a bit tedious, what you need is some way of generating a steady known good signal so you have two hands free to check various points in your guitar amp's circuitry to see if the signal is making it's way all the way through the signal-path, that's where the Function Generator proves to be very handy.

I'm going to be doing a write-up of my DIY Function Generator in this thread, which will include some pics, and details for building one yourself.


Here's a couple of pics of my DIY Function Generator:






As you can see, there's not a whole lot inside the case, of course I could have used a smaller case to house all the internals, but I like the "aesthetics" of the case I chose, it has a Laboratory test-equipment look to it, my DIY Function Generator uses a mains power transformer to power it, but since I'm going to have to re-create the circuit board layout from scratch anyway, due to my old studio computer breaking-down last year and the original layout was amongst all the files I lost as a consequence, I'm going to re-design the circuit board layout from scratch so you can safely power it using a standard DC plugpack adaptor, I do need to make a minor mod to the original circuit so that you can control the output level of all three signal waveforms though, the Sine and Triangle waveforms are variable in level, but the Square wave level is a bit too high for practical use, I will include the mod in the re-designed circuit board layout once I know the mod works perfectly.


Stay tuned for more updates!......