This circuit is one of many of its kind that can be found on this site. This one is from a September 1987 Radio Electronics. The triac must be controlled according to the load.
With this circuit general purpose diodes and rectifiers can be tested with ease R has 100 ohm for...
This circuit is from 1976 documentation, but it can be assembled with more modern transistors like...
This circuit can provide constant currents adjustable between 1 and 10 mA. The transistors can be...