Found in a Popular Electronics from the 80's, this circuit makes use of a time integrated to control a relay in a timed way. R2 determines the activation time.
In the figure we have the configuration of the circuit as a conventional Darlington. In this...
We found this circuit in a 90's Radio Electronics. The low power circuit activates a 12 V relay...
We found this amplifier in a 1990 documentation. The transistors are common, having been made...