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2answers
247 views

741 Op. Amp.: Inverting input connected to output (pin 2 connected to pin 6). What does it mean?

simulate this circuit – Schematic created using CircuitLab I am a newbie electronics students. My question is, what does it mean (what happens) when you connect pin 2 to pin 6 on a 741 op. ...
8
votes
1answer
706 views

Understanding this circuit with op. amps

I'm studying electrical engineering and I've came to a problem, where I cannot proceed. It's a "simple" task, where we're talking about an inverting op.amp with 2 voltage sources, each 1V, while all ...
2
votes
3answers
2k views

What happens if you add a voltage source to the output of an op-amp?

I'm trying to self-learn EE and have a question: What happens if you add an external voltage source to the output of an op-amp? Say as in this picture: I know that WITHOUT the Va, Vout would just ...
3
votes
2answers
775 views

Circuit analysis on op-amp with no negative feedback

In this diagram, there's an op-amp with no negative feedback. What is V+ (voltage at positive end of op-amp)? I'm self-learning circuits, and a resource I'm using says V+ = V3 / 2R. However, I don't ...
0
votes
4answers
1k views

In solving an op amp problem with two voltage sources, why can't we combine it?

Say we have a circuit like Why can't we solve by doing $$V_{out} = -(V_{in} - V_{offset}) * (R_f / R)$$ We know that \$V_{out}\$ for a typical inverting amp (that doesn't have \$V_{offset}\$) is ...
1
vote
1answer
161 views

In a real-world op-amp, how does it make sure Vn and Vp differs and don't equal each other?

I was confused about op-amps and asked this question: In an op-amp, why does Vn approach Vp until the difference is delta V / A? Why doesn't Vn just equal Vp? and received really helpful answers. ...
2
votes
2answers
1k views

In an op-amp, why does Vn approach Vp until the difference is delta V / A? Why doesn't Vn just equal Vp?

In an op-amp (non-inverting), when \$V_s\$ increases by \$\Delta V\$, \$V_n\$ approaches \$V_p\$ until the difference is \$\Delta V/ A\$ (where A is infinity). Why is there the \$\Delta V/ A\$ ...
0
votes
1answer
259 views

Explain trim pot for VU meter

I have the following schematic that is supposed to rectify the signal going to a VU meter and also trim it, so the user can adjust the position of "0dB". What I don't understand is why and how the ...
0
votes
0answers
50 views

What is the correct order and setup of AC coupling capacitor and line driver? [duplicate]

When I use an AC coupling cap along with a balance line driver, what is the correct setup? What happens when I omit the resistor in the following schematics? Is it neccessary? simulate this circuit &...
2
votes
1answer
270 views

Understanding this LPF in opamp feedback loop

I'm using a basic opamp driven mosfet to implement a precision low current sink for an LED: This seems to work just fine within the range that I want it (10mA or so). I've seen other circuits that ...
2
votes
1answer
146 views

Bypassing input capacitor with a microcontroller

I am designing an amplifier stage and I would like to be able to switch between AC or DC input coupling. How do I achieve this with a microcontroller? I was thinking about using a relay, but it seems ...
3
votes
3answers
11k views

Calculate op-amp output voltage

I am trying to calculate the output voltage of the circuit. I know that this is a voltage follower, but I am trying to understand how it works. simulate this circuit – Schematic created using ...
4
votes
3answers
4k views

How to electronically generate exponential and logarithmic functions

i mean, it is possible to generate with Op amps, or diodes, etc, to generate complex exponential and logarithmic functions, like one can create sinusoidal signals using a Wien bridge oscillator. ...
2
votes
3answers
6k views

Op amp design that gives \$V_{out} = -2 *V_{1} + 3*V_{2} - 3 V_{3}\$

I know that a regular summing amplifier does \$\ V_{out} = -(a*V1 + b*V2 + c*V3)\$ but how do I invert one of the gains?