2006-08-24 15:48:28 · 4 answers · asked by lord_andys_new_id 1 in Science & Mathematics ➔ Engineering
Well I have taught circuits and the confusion is common.
Anything infinite is just a thought experiment. What is really meant is that there is a gain "A" that you carry through all the calculations. Then we assume "A" is very big to simplify the equations (we design amplifiers this way). To make this assumption concise, we take the limit as "A" *approaches* infinity. Therefore, we don't really have infinite gain per se.
The concept is useful in that it means that any signal applied to the input will result in an infinite output. Since this can't happen, the input must be zero.
Error amplifiers (like op-amps in negative feedback mode) have almost zero voltage between their inputs, due to the high (but not really infinite) gain.
2006-08-24 16:27:17 · answer #1 · answered by Anonymous · 0⤊ 0⤋
An oscillator is sometimes thought of as an amplifier with infinity gain. The gain of an amplifier is Vo/Vin, output voltage over input voltage, If the amplifier ouputs a signal with a 0v input, its gain is infinity. The reason this comes up is that in analyzing a circuit, the condition for oscillation is an "infinite" response (called a "pole") at the oscillating frequency.
2006-08-24 19:14:32 · answer #2 · answered by gp4rts 7 · 0⤊ 0⤋
A circuit that will output "to the rail" regardless of the input as long as the input is not zero. e.g. no impeadance in positive feedback.
2006-08-24 15:56:53 · answer #3 · answered by bubsir 4 · 0⤊ 0⤋
If I remember it allows you to turn the feedback on your oscillator up to 100%.
2006-08-24 15:52:47 · answer #4 · answered by Anonymous · 0⤊ 0⤋