Voltage Controlled Amplifier Schematic

The device provides a differential input to single ended output conversion with a high impedance gain control input used to vary the gain over a 40 db to 40 db range linear in db v.

Voltage controlled amplifier schematic.

Do not apply a dc voltage outside this range for the jfet could be damaged and remember. The amplifier can achieve an 80 db dynamic control range with less than 0 2. A vca voltage controlled amplifier attenuator is the heart of any compressor or peak limiter circuit and there are quite a few different approaches. The voltage controlled variable gain amplifier circuit is built with ic op amp type lm101.

Verify that that gain of the circuit can be varied between unity and 1 20 by varying vcover the range vto vc 0. When the output voltage exceeds the supplied power the op amp saturates this means that the output is clipped or maxed out at the supplied voltages and can increase no further. This voltage controlled amplifier circuit is simply an op amp having an additional input at pin 5. The vca810 is a dc coupled wideband continuously variable voltage controlled gain amplifier.

The 2n5457 works as a voltage variable resistor having an rds on max of 800 ohms. At some voltage level the entire signal is let through. A simple linear voltage controlled amplifier can be constructed with one op amp and two jfets see the figure. A vco is also an integral part of a phase locked.

Vcrs manufactured in this way can be obtained as. Apply a sine wave to the input and a negative dc voltage to vc. The voltage gain a for an op amp is very large greater than 10 5. The vcr is one of the numerous interesting circuit elements that can be produced by using a jfet junction field effect transistor with simple biasing.

A voltage controlled amplifier can be realised by first creating a voltage controlled resistor vcr which is used to set the amplifier gain. The higher the control voltage the more signal is passed. Thus by inserting an audio signal 10 mv within pin 2 and 3 and with controlling the current on pin 5 the amount of the signal output pin 6 is controlled. The op amp amplifies the difference between the two inputs v p and v n by a gain a to give you a voltage output v o.

Assemble the circuit using a tl071 tl081 or lf351 op amp. A current ilsc is inserted into this input which controls the gain of the device linerly. A vca or voltage controlled amplifier lets you use a voltage to control the amount of another signal that is allowed through to the output of the module. A voltage controlled oscillator vco is an electronic oscillator whose oscillation frequency is controlled by a voltage input.

Because the differential voltage on the lm101 is within the low mv range the 2n5457 jfet will have linear resistance over several decades of resistance.