TIMING CIRCUIT WITH MULTIPLE TIME CONSTANTS AND SWITCHING MEANS TO CONNECT AND DISCONNECT SAID TIME CONSTANTS SELECTIVELY

摘要

A circuit utilizing a unijunction transistor or equivalent relaxation oscillator with a flip flop connected to the output thereof and having its output connected to control the time constant of the relaxation oscillator so that on alternate oscillations the time constant will be relatively low and on the remaining oscillations it will be relatively high to generate a signal having two time intervals in succession. A logic network controls driving circuits in response to the signals produced by the oscillator and the logic circuit divides the frequency of the oscillations to values suitable for timers such as interrupter timers for telephone systems.