This circuit was found in a1980s Motorola documentation. The integrated circuit is from that time. The frequency depends on the crystal.
This balance indicator for stereo amplifiers was found in an 80's Elektor. The components used are...
In the figure we have the way to control a TIC series triac with a reed switch. The current in the...
This source provides a 1.5V voltage used in the power supply of model aircraft spark plugs. The...