This alarm is either activated or triggered after a certain amount of time, giving the owner time to exit or enter and disarm it. The circuit is from a Radio Electronics from April 1975.
This circuit is from Popular Electronics from the 90s. The integrated circuit is not very common...
This direct-coupled amplifier was found in Mullard's 1960s transistor manual. The transistors are...
The LM148 and its counterparts are part of a family of low consumption quadruple operators...