Electronic timer with threshold switch - has integrator with switched continuously variable constant feeding operational amplifier comparator

摘要

In the timer circuit, an operational amplifier (N1.3) is connected as integrator and has its integration time continually and stepwise settable. The integrator is coupled before a threshold switch, comprising an operation amplifier (N1.4) operating as a comparator. The output of this (A) passes the timer output. In the feedback path, parallel to the condensor (C1,C2) of the integrator-amplifier, there is a transistor. The timer circuit is activatable over the transmittor control input (E). A resistor (R3) couple the integrator to the comparator input, and the other input may be coupled to the wiper of a potentiometer for threshold setting. USE/ADVANTAGE - Power station protection. Accurate timing in rates 1:1000.