Voltage Buffer/ Follower without opamp?

[ibnul7]

Hey guys, I was just wondering how i would make a voltage buffer/follower without using an opamp. I have used some class A (emitter follower) and AB amplifiers, but when my output is very low impedance, my output starts to saturate with an offset. I was wondering if you guys had any designs in mind with very high output impedance.

Thanks

 

[barry]

Why would you want a high output impedance? What is your load? Can you give us more specifics about your requirements?

 

[LvW]

Hey guys, I was just wondering how i would make a voltage buffer/follower without using an opamp. I have used some class A (emitter follower) and AB amplifiers, but when my output is very low impedance, my output starts to saturate with an offset. I was wondering if you guys had any designs in mind with very high output impedance.
Thanks

A voltage buffer has the task to provide a voltage with low output resistor and without gain, that means: Av=1.
Thus, it is surprising that you ask for a high output resistance.

 

[IanP]

Hey guys, I was just wondering how i would make a voltage buffer/follower without using an opamp. I have used some class A (emitter follower) and AB amplifiers, but when my output is very low impedance, my output starts to saturate with an offset. I was wondering if you guys had any designs in mind with very high output impedance.

Thanks

A follower(or a buffer) by definition has to have very low output impedance, as it has to drive any load.
If for any reason you need to increase the output impedance, just add a resistor of a desired value, but I’m afraid it will be the end of calling this thing a follower ..
:wink:
IanP