Understanding Op-Amp: Get Help with Physics & Functions

  • Thread starter Thread starter hurliehoo
  • Start date Start date
AI Thread Summary
Op-amps provide significant voltage gain between their differential input pins and output, enabling power gain that a simple wire cannot achieve. While the resistance between the input pins is high, the op-amp can amplify weak signals and drive power loads effectively. This capability is crucial for applications requiring signal processing and amplification. Using a straight wire results in no power gain, limiting the ability to handle weak signals. Understanding these principles is essential for grasping the functionality of op-amps in electronic circuits.
hurliehoo
Messages
23
Reaction score
0
Hi can anyone help me get my head round how op-amps work? I know this is a silly question but ...

Their functions (ie what a summing amp does etc) seem fairly clear. However maybe my question has more to do with the physics of what's happening but if the resistance between the two voltage input pins is practically infinite and the current is effectively being channeled, then why not just have a simple line instead of an op-amp component?
 
Engineering news on Phys.org
I'm afraid I don't understand what you mean by "and the current is effectively being channeled", and by "why not have a simple line instead of an op-amp component".
 
hurliehoo said:
Hi can anyone help me get my head round how op-amps work? I know this is a silly question but ...

Their functions (ie what a summing amp does etc) seem fairly clear. However maybe my question has more to do with the physics of what's happening but if the resistance between the two voltage input pins is practically infinite and the current is effectively being channeled, then why not just have a simple line instead of an op-amp component?

The difference is the voltage gain of the opamp. There is very high voltage gain between the differential input pins and the output, so the output can have power gain compared to the input signal.

So in a voltage follower, for example, if you just have a straight wire, the voltage gain is 1 and the current gain is 1, and there is no power gain. When you use an opamp in the voltage follower configuration, the voltage gain is 1, but the opamp's output amplifier stage can supply more current than the input signal can (generally), so there is power gain.

The power gain is important for being able to process weak signals, and for driving power loads.

Hope that helps. Read over the wikipedia page, and come back with specific questions if you have them. You might also see if your school library has a copy of "The Art of Electronics" by Horowitz and Hill -- the chapter on Feedback and Opamps may be helpful for you.
 
the op-amp allows you to spy on a signal without being seen. ;)
 

Thread 'Following up on the recent thread about Earth Resistance measurements'

I have recently moved into a new (rather ancient) house and had a few trips of my Residual Current breaker. I dug out my old Socket tester which tell me the three pins are correct. But then the Red warning light tells me my socket(s) fail the loop test. I never had this before but my last house had an overhead supply with no Earth from the company. The tester said "get this checked" and the man said the (high but not ridiculous) earth resistance was acceptable. I stuck a new copper earth...
View full post »
Thread 'Electromagnet magnetic field issue'

Thread 'Electromagnet magnetic field issue'

Hi Guys We are a bunch a mechanical engineers trying to build a simple electromagnet. Our design is based on a very similar magnet. However, our version is about 10 times less magnetic and we are wondering why. Our coil has exactly same length, same number of layers and turns. What is possibly wrong? PIN and bracket are made of iron and are in electrical contact, exactly like the reference design. Any help will be appreciated. Thanks. edit: even same wire diameter and coil was wounded by a...
View full post »
Thread 'Beauty of old electrical and measuring things, etc.'

Thread 'Beauty of old electrical and measuring things, etc.'

Even as a kid, I saw beauty in old devices. That made me want to understand how they worked. I had lots of old things that I keep and now reviving. Old things need to work to see the beauty. Here's what I've done so far. Two views of the gadgets shelves and my small work space: Here's a close up look at the meters, gauges and other measuring things: This is what I think of as surface-mount electrical components and wiring. The components are very old and shows how...
View full post »

Similar threads

Op-amp compensation of cascade fudges audio signal oddly
Replies
3
Views
2K
Op-amp Oscillator Circuit Design (10-50 MHz)
Replies
6
Views
3K
How do rail-to-rail op amps get so close to the rail voltages?
Replies
9
Views
2K
What's wrong in my LTspice simulation of an Op-Amp integrator circuit?
Replies
9
Views
6K
Confusion on: High Pass Filter at Op Amp Input
Replies
6
Views
2K
"Ground" and "Center Tapped" Power Transformer Secondary in guitar amp
Replies
6
Views
3K
Inverting a signal up to 100mV using op amps
Replies
6
Views
2K
Op-amp circuits and noise at high frequency/low amplitude
Replies
5
Views
2K
Design of an Op Amp Circuit for Voltage Amplification
Replies
9
Views
4K
Op-amp: Current and bandwidth question
Replies
8
Views
3K

Hot Threads

Recent Insights

Back
Top