Datasheet Summary
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FETs As VoltageĆControlled Resistors
Introduction: The Nature of VCRs
A voltage-controlled resistor (VCR) may be defined as a three-terminal variable resistor where the resistance value between two of the terminals is controlled by a voltage potential applied to the third. For a junction field-effect transistor (JFET) under certain operating conditions, the resistance of the drain-source channel is a function of the gate-source voltage alone and the JFET will behave as an almost pure ohmic resistor. Maximum drain-source current, IDSS, and minimum resistance rDS(on), will exist when the gate-source voltage is equal to zero volts (VGS = 0). If the gate voltage is...