Relation
a x (a + b) = a + a x b ≡ a
RF or even switching transistors like the 2N2222 can be used in this circuit. The capacitors are ceramic...
This TTL module can be used in counter and many of them can be cascaded to counts up to 99, 999,...
This circuit was obtained from an English magazine from 1985. It consists of a pulser that drives...