Provides a 0 - 10 volt ramp, time period selectable from 10 seconds through 10 ms, continuously variable through each range. Between ramps there's a reset pulse, selectable from 0.5 seconds through 5 ms, again continuously variable through the range. There's a push button (toggles on - off - on) to select REP (repetitive) mode on the computer. Certainly the most interesting circuit so far. Also weirdo debugging issue...transpiring to be the (7915) negative rail regulator oscillating like a gazelle (despite the specified decoupling capacitors). Fixed with a little more decoupling and voila:
Here's the finished board (plus elevated sub-board):
The big green things are Russian polystyrene capacitors (from KL Tubes, Lithuania...excellent service...and arriving much faster than things from Rapid Electronics in the UK!). The big grey things are (5 microfarad) capacitors made by Vishay...perhaps a bizarre coincidence but named after the village of Vishay in Lithuania, (the ancestral home of the company's founder).
Here's the finished board (plus elevated sub-board):
The big green things are Russian polystyrene capacitors (from KL Tubes, Lithuania...excellent service...and arriving much faster than things from Rapid Electronics in the UK!). The big grey things are (5 microfarad) capacitors made by Vishay...perhaps a bizarre coincidence but named after the village of Vishay in Lithuania, (the ancestral home of the company's founder).
And here is the circuit...
I love the fact that the 2N2222 is still in production, some fifty years after Motorola introduced it in 1962.
