Found in old documentation, this source uses an integrated circuit from that time, which is uncommon nowadays. The power source has a ripple below 1 mV.
This circuit was obtained from an English publication from the 70's. The circuit is still current for...
This circuit was found in a 1979 magazine. We can use any JFET like MPF102 or BF245. The relay is 12 V...
Found in Motorola documentation from the 90s, this circuit can be implemented with current...