This high quality circuit with complementary symmetry was found in an Electronics World of 1966. It can be made with modern transistors like the BD or TIP series.
We found this circuit for an anti-theft radar that operates at 400 MHz in a Radio Electronics from...
In the figure we have a diagram of a thermostat using an NTC and an operational amplifier 741. The...
This version of a call-fish is from 1981 using, for this reason, a 90 V battery that is no longer...