Question

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

• A. 0.8 mA
• B. 0.6 mA
• C. 0.4 mA
• D. 1 mA

Answer 1

Answer: (B)

0.6 mA

Answer 2

By using $g_{m} = \frac{\Delta i_{p}}{\Delta v_{g}}$⇒ $3 \times 10^{- 4} = \frac{\Delta i_{p}}{- 1 - ( - 3)}$

⇒ $\Delta i_{p} = 6 \times 10^{- 4}A = 0.6mA$