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.
Found in National Semiconductor documentation from the 1980s, this circuit can be implemented with...
This circuit was found in a 1968 EEE. The circuit makes use of logic gates of the time and can be...
We found this circuit in a publication on operational amplifiers from 1978. The circuit is made...