Tube Amps / Music Electronics
|For current discussions, please visit Music Electronics Forum.||New: view Recent Searches.
New: visit Schematic Hell!
The sunn still shines online!
|Listen to great tunes streaming live right now!|
|12/11/1997 12:58 AM|
I've been rooting around in some older circuit books lately and have come aross a term that I haven't heard before. Bootstrapping.
What is it and what is the purpose? It looks like it may have something to do with high frequency positive feedback. Anybody know what's going on?
|12/11/1997 3:08 AM|
Bootstrapping is positive feedback but it does not have to be at high frequency. I have seen it used in old bipolar transistor AF input stages to increase the input impedance. Newer circuits usually use a FET. It is still used in transistor power amp output stages. The class A drive transistor is bootstrapped half way up its load resistor with a capacitor from the output. The collector load then looks like a constant current so the gain is increased and the amp output can get closer to the supply rail. I have that output stage in my home-brew bass amp.
|Page 1 of 1|