This circuit was found in a 90s Wels' Think Tank. The frequency depends on C2 and R3. The handset or speaker must be at least 80-ohm. Observe the low supply voltage.
This circuit provides a negative supply for circuit biasing. The current is very low. The voltage...
This very low voltage circuit with the LMV321 was obtained from its own datasheet. The circuit can be...
This circuit was found in a Modern Electronics from 1990. It activates an old electromechanical pulse counter,...