A good current buffer has
A. low input impedance and low output impedance
B. low input impedance and high output impedance
C. high input impedance and low output impedance
D. high input impedance and high output impedance
Please scroll down to see the correct answer and solution guide.
Right Answer is: B
SOLUTION
Concept:
Properties of current Buffer:
1) Unity current gain
2) Low input Impedance
3) High output Impedance
4) Very large voltage gain
The reasoning of low input impedance and High Output Impedance is as explained:
Consider the following current buffers:
We want current Is (source current) to enter into the circuit of the current buffer, i.e. our
requirement is Ii = Is, which is possible when Ri is very small, i.e. ideally zero.
Now, at the output side, we want Io =AI Ii, i.e. the current should flow across the load.
∴ Ro should be very high, i.e. ideally infinite.
Extra Information:
Properties of Voltage Buffer:
1) Unity voltage gain
2) Very large current gain.
3) We high input impedance
4) Low output impedance
