Contactless checking of pulse signals for breakdown detection - utilises inductive sensor with integration and rectifier circuits driving bistable with LED output indicator

摘要

Signal pulses are applied to an inductive sensor (1) which provides an input signal to an ac amplifier (2). An integrator circuit (5) slows the leading edges of the pulses while a differentiator circuit (6), comprising an amplifier (9) and a transformer (10), produces a train of pulses of short duration at the same frequency as the output of the inductive sensor. A full wave rectifier (3) produces a series of unidirectional pulses which are amplified in an ac amplifier (14). The amplifier output passes via a capacitor (17) to a bistable (15). If the bistable input exceeds a threshold value the output changes state to illuminate an LED (18). The LED (18) is extinguished and the bistable reset by a reset signal at its second input (19).