Max, once again you reinforce the reason a lot of us got into Electronics.... its fun! Your article caught my attention as I also needed a signal generator for some home projects, but not enough to fork over the cash for some swanky Agilent unit. I built my own around 1981 around a Radio Electronics (remember those guys?) article using an Exar XR2206 chip. Still have the unit to this day for audio work. Keep up the good work :-)
The ICL8038 is one of those chips that have found their way into modular synthesis applications. As such, there are numerous sites that discuss it's use, provide plans, and even offer sale of these, as well as other hard-to-find devices.
Perhaps one particularly useful design, one which overcomes some of the limitations of the 8038, can be found here:
The triangular waves were converted to sine waves involving a non-linear network of transistors and thin-film resistors.
I'm not an IC design expert, but that sounds pretty expensive. Maxim used to sell a copy, but it's also EOL. The Maxim site shows how to use a square wave oscillator followed by a high-order switched-capacitor filter to get sine waves.
@Max.... "Ivan rooted around under a bench and extracted a somewhat battered old case....something that scared the socks off me."
Wuss!! Doesn't look toooo complicated. Just a couple of breadboards with a frequency generator and some switches and LEDs. But your new toy does look very tasty.
I can never get EET to post pictures but in copying your text I got a couple of pictures in and of course they posted in the comment without problem, and instead of struggling to get them in I had to delete them out. Doesn't it make ya spit???
@antedeluvian: It was a low frequency oscillator for all seasons.
There were some great chips back then -- my frequency/function generator uses a microcontroller to create it's waveforms -- it really is amazingly tasty (we just had it up on the workbench -- watch for my blog tomorrow)
Let me be the first to reminisce about the Intersil/Exar/Harris 8038. It was a low frequency oscillator for all seasons. For some reason everyone has continued them, but there muist be many around hidden in drawers etc. I may even have a couple myself. If you want o go this way, put out a call- someone will be able to help.