| 摘要 |
<p>An input converter circuit for producing a logic level indication of the on of off condition of an input. The input may be AC or DC at any reasonable level. A bilateral photocoupler output is applied to an operational amplifier integrator, which establishes the integration time of the signal. The amplifier output is coupled to a Schmitt trigger having threshold levels at about one third and two thirds of the power supply voltage. The output of the Schmitt trigger provides a logic one output if there is an input signal present and a logic zero output otherwise.</p> |
