why can't you measure the voltage on op amps inputs? I always get zero volts , why is that, what can I do to get the voltage on the input pins of Op amps?
So what can I do to measure the voltage of a virtual ground?the inverting input is a 'virtual ground' the amp always tries to drive the pin back to zero, you'll never measure anything other than a tiny signal voltage there.
Why is it driving the input pin back to zero voltage?the inverting input is a 'virtual ground' the amp always tries to drive the pin back to zero,
Because that's what op-amps do, they always want the voltage between inverting and non-inverting inputs to be zero.Why is it driving the input pin back to zero voltage?
Why is that?Because that's what op-amps do, they always want the voltage between inverting and non-inverting inputs to be zero.
We can't predict what you're doing. Post the circuit.Why is that?
How can you measure the input pin voltage?
If it measures zero volts , how can you know the input pin's voltage?
This is the classical effect of negative feedback.Why is it driving the input pin back to zero voltage?
Why is it always zero? because the op amps differential inputs want to default to zero volts? but how does it default back to zero volts?If he's just wanting to measure the input voltage in a working op-amp circuit he will never achieve it because it's always zero.
The Feedback signal is a Differential voltage being feedback to the input pin of the op amp? this differential voltage is compared to the other input pin of the op amp which is Cancels out the voltages? which it is near ground in millivolts or microvolts ? ( virtual ground )the feedback signal is used to sense and reduce the difference to the input signal by adjusting properly the output.)
Virtual ground means the voltage is in millivolts or microvolts? or nanovolts?"virtual" ground (which means: "near" ground)
No, there is no "default" value. As mentioned already, it is simply the feedback effect in case of a high-gain forward amplification.Why is it always zero? because the op amps differential inputs want to default to zero volts? but how does it default back to zero volts?
No, the feedback voltage is the voltage at the inverting terminal only.The Feedback signal is a Differential voltage being feedback to the input pin of the op amp? this differential voltage is compared to the other input pin of the op amp which is Cancels out the voltages? which it is near ground in millivolts or microvolts ? ( virtual ground )
Assuming a dc output voltage of (1...5) volts and Aol=1E5 the input diff. dc voltage isVirtual ground means the voltage is in millivolts or microvolts? or nanovolts?
The output pin of the output is the feedback voltage? if the output pin voltage is 5 volts, the feedback voltage is 5 volts? but the input pin on the op amp is zero volts or in millivolts, that doesn't make sensethe feedback voltage is the voltage at the inverting terminal only.
So the GAIN and the output voltage = the input pin voltage?Assuming a dc output voltage of (1...5) volts and Aol=1E5 the input diff. dc voltage is
(1...5)/1E5 volts = (10...50)µvolts.
Who says that? There is only one "inverting" pin - and that is the inverting INPUT of the opamp.The output pin of the output is the feedback voltage?
The above sentence is neither an equation nor does it make sense.So the GAIN and the output voltage = the input pin voltage?
by Jake Hertz
by Jake Hertz
by Duane Benson