The purpose of this circuit is to measure the resistance of an antenna at the resonant frequency. The circuit is from an old American documentation for hams.
Found in a 1980s American documentation, this circuit has a current consumption of only 1 mA. The...
Found in na 1970 EDN this circuit has a parallel regulation providing a symmetrical output of 15 V....
This circuit triggers a relay when the set temperature is reached. The circuit is from an old...