This circuit is from an American manual from 1975. The transistors are types of the time, but equivalents can be used, as well as the relay that can be according to the supply voltage.
Suggested for use in cars and motorcycles, this circuit was found in a 90s Popular Electronics. The...
This is a typical 3 ½ digit TTL counter. We found it in the September 1973 issue of Radio...
This receiver, whose tuning range depends on L1 and L2, was found in the 1992 special edition of...