This is a typical 3 ½ digit TTL counter. We found it in the September 1973 issue of Radio Electronics magazine. The circuit is to be powered by 5 V. It can be expanded to more digits.
In the figure we have a piezoelectric transducer drive circuit that can be used in conjunction with the...
This circuit is from a Ferranti publication of 1968. The circuit generates a signal according to the...
This is one of the possible triac power control configurations using as a trigger element a...