Arrangement for operating an electric load, e.g. a coil or lamp, compares trapezoidal wave and load voltage signals and controls switch so load current varies with trapezoidal signal

摘要

The arrangement has a switch (6) in a current feed path from a D.C. source to the load (2), and a sensing resistor (8) in series with the switch to detect a load current as a voltage. A signal generator (10) generates a trapezoidal wave signal in response to externally applied command signals to switch the load on and off. A controller (20) compares the trapezoidal and measured voltage signals and controls the switch accordingly so that the load current varies with the trapezoidal signal.