TRANSISTOR CHOPPER DRIVES ACCURATE CLOCK
Richard Hays Williams · Electronics · 1958
A transistorized control circuit including a frequency-determining crystal oscillator feeds a voltage chopper which doubles the 28-v d-c supply and divides the driving frequency is described. The a-c pulsed output then drives a synchronous clock motor. The system measures time intervals from 10 sec to minutes with an accuracy of 0.02 percent over a temperature range from -55 to +70 C. (auth)