How to design a buffer?

[saleheen]

How do I design an unity buffer (non-inverting) using a transistor(2N3904) ? The input comes from an amplitude modulation circuit with carrier frequency of 40kHz. Therefore, the bandwidth should also be considered.

 

[ricklin]

Only 1 transistor?? A simply emitter follower will fulfill the job, if you don't care the DC shift and a small gain loss.

 

[saleheen]

I need high bandwidth..

 

[LvW]

What means "high" ? 1 MHz ? 100 MHz ?
Only one transistor allowed ? One or two power supplies with which value(s) ?

 

[ricklin]

I think you need to detail your spec too. For one transistor and same power, emitter follower almost the highest bandwidth.