# How to improve emitter-follower efficiency?

I’m trying to wrap my head around the emitter follower.

I’m currently using it to simulate a ~12V AC coming from a intercom ringer (about 700Hz).

simulate this circuit – Schematic created using CircuitLab

My input is a function generator and I would like my output to drive quite a bit of current. Right now the best I could do is drive a few mA but in the process I’m setting my $$\R_E\$$ on fire. Is there a way to improve the efficiency of this circuit? Or I’m better off using another buffer?

• This circuit will not work as needed - use standard (two transistors) class a / ab amplifier – fifi_22 Nov 14 '20 at 20:46
• That's what a Class A amplifier does. Search "Class B" or "Class AB Amplifier" designs. – user_1818839 Nov 14 '20 at 20:47
• That $R_E$ just "pisses away" as much current as it can deliver to the output. What you need is an $R_E$ that varies its value depending on how much current is needed at the output. That's a job for another transistor. Like a class B (or AB) output stage. – Bimpelrekkie Nov 14 '20 at 21:32
• So the answer to my question is to add a second transistor? – gurghet Nov 14 '20 at 23:48
• @gurghet At least one. And a few other parts, too. – jonk Nov 15 '20 at 6:59