摘要 |
In a zener referenced voltage threshold detector, the voltage at which a switching transistor turns on is determined by the breakdown voltage of a zener diode coupled between ground and the base of the switching transistor in conjunction with the base-emitter voltage of the switching transistor itself. In order to render the threshold detector circuit immune from noise at the trip point, a portion of the switching transistor's collector current is supplied to a second transistor which when turned on reduces the voltage at the base of the switching transistor.
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