This circuit provides a delay for the activation of an alarm, giving the owner time to leave the premises. The circuit is from the 1995 Encyclopedia of Electronic Circuits Volume 5.
In the figure we show how to use a 555 to control an SCR or another type of thyristor. Resistors R1, R2...
This circuit was taken from the 1974 Ferranti transistor manual. Transistors are common types at...
This interesting intercom circuit was obtained from an Argentine publication from the 1970s....