Found in a 90s Popular Electronics, it serves both TTL and CMOS logic. The injector can provide 10 kHz or 100 Hz signals. The circuit drives a transducer and two LEDs.
We found this circuit in the February 1987 issue of Radio Electronics magazine. It is based on an...
This circuit is from an Argentine publication from the 1970s but can still be assembled with...
We found this circuit in a publication from the 90's. The circuit is used with sinusoidal...