Found in a 1924 documentation, this circuit is powered by 3 batteries, two of which are high voltage. The output is a high impedance headphone jack.
We found this simple continuity tester in a 1995 documentation. It uses two LEDs to indicate...
We found this oscillator in the 1994 National Semiconductor Handbook of Linear Applications. The...
This circuit was found in a 90s Electronic Design. The circuit directly controls a triac that is...