# Tag Info

Accepted

### Op-amp - Lead compensator design

You need to design your active filter - the compensator - so that it exhibits a gain of 20.6 dB at 5 kHz. Calculate the magnitude of the filter with the selected pole-zero pair. This pair is ...

### Using an opamp, I want to double a DC input signal that varies from 230 mVDC to 2300 mVDC. I want to use a single supply voltage of +5 vDC

Part of your confusion could be calling the resistors Rin and Rf. That suggests to me that you've also been looking at a different configuration, an inverting amplifier, which often calls the ...

### How do you turn on an LED when the input voltage is less than 12V?

Riffing on Dave's answer, here's the low component way to turn an LED off when the sense voltage exceeds some threshold. Not for battery operation due to the continuous power drain, but 'fuse box' did ...

### Trying to simulate a basic op-amp intrgrator but cannot seem to find any error in my circuit

The integrator is too fast. +12V at the input will produce this input current: $$I_{IN} = \frac{V_{IN}}{R_1} = \frac{12V}{820\Omega} = 14.6mA$$ Ignoring R2, all this current passes through C1, ...

### Trying to simulate a basic op-amp intrgrator but cannot seem to find any error in my circuit

Ignoring R2, a 12V input means almost 15mA, so a dv/dt at the output of almost 150V/ms until it saturates. At 20ms/div it will change 10V in about 1/200 of a division. So the ramps are there, just not ...
Accepted

### Find resistors for an inverting op amp band pass filter

The input pair of components create a high pass filter, the feedback pair of components create a low-pass filter. Using f(-3dB)=1/(2 * pi * R * C) for each pair of components (input pair and feedback ...
1 vote

### Trying to simulate a basic op-amp intrgrator but cannot seem to find any error in my circuit

You have built a 200 Hz low-pass filter with gain of 10x are feeding it with 45 Hz. So with those values, you will not see any ramps as the ramp is very quick compared to the frequency of the signal. ...
1 vote

### How can I implement current control for proportional valves?

The 16-mm valve recommended PWM frequency is 1000 Hz; the 22-mm valve is 500 Hz. Your circuit has just a few issues: An LM358 performs poorly going in and out of saturation, and even with an "...
1 vote

### How do you turn on an LED when the input voltage is less than 12V?

This design will switch on one or more LEDs with a reasonably constant current of 10mA, as soon as the supply voltage exceeds the LEDs' combined forward voltage. That would be 1.6V for a single red ...
1 vote

### How do you turn on an LED when the input voltage is less than 12V?

How precise does it need to be? The LM431 is a handy chip that includes both a voltage reference and a comparator. A couple of transistors can be used to switch the LED on: simulate this circuit &...
1 vote

### Find resistors for an inverting op amp band pass filter

Well, the transfer function of your circuit is given by: \mathscr{H}\left(\text{s}\right):=\frac{\displaystyle\text{V}_\text{o}\left(\text{s}\right)}{\displaystyle\text{V}_\text{i}\left(\text{s}\...

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