This circuit was found in an Australian publication from 1991. It is a transmitter that transmits a signal when it detects moisture. The range is on the order of a few tens of meters.
This project is from a 1982 documentation, based on an astable multivibrator with two transistors. The...
Found in a 1967 US magazine this circuit generates positive and negative voltage pulses from a...
Rumble is a low frequency noise between 25 and 200 Hz that appears in old turntables, affecting...