Assertion (A): The gall tinsley potentiometer is a coordinate potentiometer and has two exactly similar potentiometers.

Reason (R): An ac potentiometer may measure the unknown voltage in polar form or rectangular coordinate form.

Assertion (A): Integral control action is sometimes called reset control.

Reason (R): Reset rate is expressed as number of repeats per unit time.

1. Circuit is always open
2. Network is always open
3. Circuit is always closed
4. Network is always closed

Match the following:

Assertion (A): Intrinsic semiconductor is an insulator at 0 K.

Reason (R): Fermi level in intrinsic semiconductor is in the centre of forbidden energy band.

Assertion (A): Thevenin's theorem helps us to find current in a branch of a network for different values of impedances of that branch.

Reason (R): Thevenin's equivalent circuit replaces a network by a voltage source in series with impedance.

1. It has low saturation current.
2. It has high value of cut in voltage.
3. It can withstand large reverse voltage.
4. When compared with germanium diode, silicon diode shows a lower degree of temperature dependence under reverse conditions.