This double tone generator uses a specific integrated circuit, having been found in a 1977 CMOS Cookbook. The transistors can be the BC548.
This circuit combines field effect and bipolar transistors to obtain a 20 gain with a pass band...
We found this simple toy organ circuit in the February 1968 issue of Radio Electronics magazine. The...
The sensor for this alarm is a thin wire that, when interrupted, triggers a buzzer and turns on a...