Q. What is the advantage of using JFET as an amplifier?
As an amplifier of small time-varying signals, the JFET has a number of valuable assets. First of all it has a very high input resistance (a reverse biased p-n junction), which is one of the characteristics of an ideal voltage amplifier. For this reason, it is widely used in instrumentation circuits such as digital voltmeters and oscilloscope input amplifiers. In general, a JFET generates less internal noise. Hence it is used in numerous audio and video amplifiers. JFETs have very low power consumption and are used to good advantage in the design of operational amplifiers where input offset voltage and input currents need to be minimized.