JFETs find application in

Measuring instruments as a buffer since it has low output impedance and high input impedance.

RF amplifiers, FM tuners and communication equipment because of the low noise level.

Cascade amplifiers in measuring and test equipment since the input capacitance is low.

Operational amplifiers and tone controls as voltage variable resistor as it is a voltage controlled device.

FM and T.V receivers in mixer circuits because its intermodulation distortion is low.

Oscillator circuits as frequency drift is low.

Low frequency amplifiers in hearing aids and inductive transducers as the coupling capacitor is small.

Digital circuits in computers, LSD and memory circuits because of its size.