This circuit is from a 1975 Miniwatts magazine, therefore using Philips components from that time, now difficult to find. The circuit directly controls a heating element via a Triac.
Obtained from an English publication, this circuit actually needs a current limiting resistor,...
This 2003 circuit serves to digitally show the intensity of a sound captured by a microphone....
Suggested by a Popular Electronics from the 90s, this circuit uses a buzzer to indicate the...