This oscillator version is from an RCA documentation from the 1970s. Transistors support modern equivalents and the power can be supplied in a voltage range of 5 to 12 V. For Q2 we suggest the BD136.
This circuit needs only 0.7 V at 40 uA to drive the relay. We found it in the November 1993...
This circuit is from a 90s Radio Electronics. The resistors must be precision types and the...
This circuit is from an old American documentation using LEDs in the rectification. The circuit...