The point representing the cut-off grid voltage on the mutual characteristic of a triode is:

Why is a vacuum tube called a valve in electronics?

The grid voltage of any triode valve is changed from $-1 \, V$ to $-3 \, V$ and the mutual conductance is $3 \times 10^{-4} \, \text{mho}$. The change in plate circuit current will be ..... $mA$.

In the figure,four plate characteristics of a triode at different grid voltages are shown. The difference between successive grid voltages is $1 \ V$. Which curve will have the maximum grid voltage and what is its value?

In a triode amplifier,$\mu = 25$,$r_p = 40 \text{ k}\Omega$,and load resistance $R_L = 10 \text{ k}\Omega$. If the input signal voltage is $0.5 \text{ V}$,then the output signal voltage will be.....$\text{V}$.

In a diode valve,the cathode temperature must be ($\phi$ = work function):