This interesting digital counter with relays with complementary outputs was found in the Radio Electronics magazine of October 1961. The supply voltage is in accordance with the relays used.
The output power of this wireless intercom for the 27 MHz (11 meters) range is in the order of ½ W,...
In the figure we have the way to implement an Exclusive OR or XOR gate with CMOS or TTL...
This useful circuit is used to test the insulation of cables, appliances, leaks in high voltage...