This unusual circuit from a Popular Electronics of the 90s uses LED indicators, operating as a bridge. The components used are common. It is based on the tuning of the signal by a PLL.
This circuit was originally found in a Philips documentation from 1969. It is intended for sensing...
This circuit is obtained from old documentation, activating it when there is a power cut in the...
This circuit is from a 1977 application manual for timers. The circuit provides a negative pulse...