Question

Draw a plot of the transfer characteristics (V₀ versus V_i) for a base-biased transistor in CE configuration. Show for which regions in the plot, the transistor can operate as a switch ?

Answer 1

 Transfer characteristics curve, for a base-biased transistor in CE configuration,

In cutoff region and in saturation region transistor acts as switch off and switch on respectively.

In cutoff region, as long as V_i is low, it enables to forward bias the transistor, V₀ is high. In this region transistor is not conducting. Hence said switched off.

In saturation region, V_i is high enough to live the transistor, the V₀ is low. It is said to be stretched on.

Hence, low input give high output and high input gives low output.