This shield circuit is from a 1968s Motorola documentation. The relay is according to the supply voltage. R1 can be reduced to lower trigger voltages.
Suggested by Burr Brown in 1969 documentation, this circuit makes use of an integrated component...
We found this circuit in the June 1988 Radio Electronics magazine. The power supply must be...
This circuit was obtained from a 2005 Linear Technology manual. The circuit is self-powered and can...