Simple Time-Delay Circuit with Very High Duty Cycle

A voltage-controlled time-delay arrangement with a duty cycle equal to unity is described. This performance of the circuit is based on the use of a new monostable switch with complementary transistors. The monostable switch, derived from a free-running multivibrator with very small mark/space ratio is employed as the trigger time base generator, the recovery time of which is very short. Such a time base generator is suitable for various applications in the measurement instruments. Connected to the Schmitt trigger, this timing circuit is very useful in the design of wide-range time-delay arrangements. The experimental performance of the presented time-delay arrangement is as follows: the delay-time variation in one range from about one microsecond to several milliseconds; the delay time/control voltage linearity better than ± 0.15 percent for the control voltage greater than 0.5 volt; the temperature stability of about 0.2 percent in the temperature range from 25-100°C.