# Understanding Op-Amp: Get Help with Physics & Functions

• hurliehoo
In summary, an op-amp allows you to amplify a weak signal and to increase the power output of a signal.
hurliehoo
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?

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. ;)

## 1. What is an op-amp and how does it work?

An op-amp, short for operational amplifier, is an electronic component used in many circuits to amplify signals. It has two inputs, a non-inverting input and an inverting input, and one output. The output is the difference between the two inputs, amplified by a factor called the gain. It works by using a high-gain differential amplifier to compare the two inputs and produce the output.

## 2. What are the different types of op-amps?

There are many different types of op-amps, each with its own specifications and uses. Some common types include general-purpose op-amps, instrumentation op-amps, and precision op-amps. General-purpose op-amps are used in a wide range of applications, while instrumentation op-amps are more specialized for precise measurements. Precision op-amps are designed for high accuracy and low noise.

## 3. How do I choose the right op-amp for my circuit?

Choosing the right op-amp for your circuit depends on several factors, including the desired gain, bandwidth, and input/output impedance. It's important to consider the specifications of the op-amp and how they match your circuit's requirements. You may also need to consider factors such as cost and availability.

## 4. How do I analyze op-amp circuits?

Analyzing op-amp circuits involves understanding the basic principles of op-amp operation and using circuit analysis techniques such as Kirchhoff's laws and Ohm's law. It's also helpful to understand the different configurations of op-amp circuits, such as inverting and non-inverting amplifiers, and how they affect the output.

## 5. How can I troubleshoot issues with my op-amp circuit?

If you are encountering problems with your op-amp circuit, some common troubleshooting steps include checking for loose connections, ensuring the power supply is correct, and verifying that the op-amp is the correct type for your circuit. It may also be helpful to use a multimeter to measure voltages at different points in the circuit and compare them to expected values.

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