Voltage Controlled Resistor

The input port voltage controls the value of the resistor between the output ports.

Voltage controlled resistor. This is a three in one instructable 1. There are two distinct regions. V i x r x vc. In the ohmic region1 the drain to source current i ds depends on the gate to source.

The ohms law is applied in this scenario. The resistor will only produce 4v drop if the current through the resistor will 400ma 4a. One of the simplest uses of a voltage controlled resistor is an electronically controlled attenuator or volume control. A voltage controlled resistor vcr may be defined as a three terminal variable resistor where the resistance val ue between two of the terminals is controlled by a voltage potential applied to the third.

A simple addition to the above resistor model gives you a voltage controlled resistor. In each of these circuits the drain and source terminals of the fets q1 q2 q3 and q4. Here s a subcircuit for this device subckt vc res1 10k 1 2 4 5 eres 1 3 value i vsense 10k v 4 5 vsense 3 2 dc 0v ends. Two types of fets are often used.

This is because voltage current x resistance. Basic voltage controlled resistor vcr circuits. For a junction field effect transistor jfet under certain operating conditions the resistance of the drain source. Vcrs are most often built with field effect transistors fets.

A voltage controlled resistor vcr is a three terminal active device with one input port and two output ports. The basic circuit forms a voltage divider as shown in figures 3 4 5 and 6. All you need is a controlling voltage to multiply the resistor value. Make a voltage controlled resistor and use it.

A voltage controlled resistor béla géczy ltspice is one of the world s leading circuit simulation tools. The jfet and the mosfet there are both floating voltage controlled resistors and grounded floating. The output of the op amp turn on and control the mosfet until the voltage drop across the shunt resistor became 4v. In 1998 linear technology hired mike engelhardt to re write spice to allow simulation of linear circuits with primary emphasis on switching power supplies.