# op-amp's questions - English 1answer

3.735 op-amp questions.

### Opamp BJT Circuit problem

0 answers, 12 views op-amp bjt
Non inverting Amplifier- LF351N BJT - BC337 Gain = 5.8 Opamp Supply Voltage is +12V & -12V Transistor Collector voltage is =12Vdc Opamp I/p = 1Vpp(Sin wave) Opamp O/p = 5.8Vpp Opamp O/p is ...

### PI Metal Detector Amplification Circuit

2 answers, 1.308 views op-amp pulse induction metal
I've been research metal detector designs for a few days now and I can't quite wrap my head around the amplification they are using for the first stage right out of the coil. Below is an example ...

### 2 op amp current source oscillating

1 answers, 70 views op-amp mosfet current oscillator source
I know this topic has been discussed a lot, but there seems to be varying opinions about the solutions.. The problem is we are trying to make a current source with an op-amp driving a FET as the load....

### 3 Gain of an active filter without calculating the transfer function with two OP-AMPs

4 answers, 239 views op-amp gain
I need to calculate the gain of the filter without explicitly calculating the transfer function, ie I have to replace the capacitors with an open circuit. The problem is that I've been trying to solve ...

### 1 Import MCP602 Model into LTSpice - Timestep Error

1 answers, 293 views op-amp ltspice
Good evening Community, I would like to use the MCP602 model in LTSPice, but I am having simulation errors. Please see schematic below. I have downloaded the model from Mircochip and opened it via ...

### Schmitt trigger with 741 op-amp not behaving as in simulation

1 answers, 84 views op-amp ltspice schmitt-trigger ideal
I am implementing a Schmitt trigger using the circuit shown below. This circuit consists of one LM741 op-amp, which acts as an asymmetrical Schmitt trigger with a single power supply. According to ...

### Question regarding slew-rate

2 answers, 56 views op-amp slew-rate
I have a question regarding SR effect. Let's say that we have some simple amplifier with op-amp with the following parameters: \$G=+10 \ V/V, \ f_c=1MHz, \ SR =1V/\mu s, \ V_{supply}=\pm 15V\$ ...

### 1 Unbalanced to balanced audio signal conversion

2 answers, 72 views op-amp audio analog converter diy
When I was looking for some information how to convert unbalanced audio signal to balanced, it was hard to find info other than "use transformer" or "buy X device to do this". Then I found this ...

### 3 Op-amp bias issue to to charging of DC blocking capacitor

We're using the above circuit to drive a sinusoid with constant current into a custom sensor which is best modeled as a series capacitance & resistance (~100ohm, 1uF). The op-amp is single supply, ...

### Q: How to use circuit analysis on a circuit ideal diodes with ideal op-amps

1 answers, 39 views op-amp circuit-analysis
I have been practicing how to analyze op-amps with diodes as I never really learnt them and thought it would be a handy skill to finally learn. I have been attempting a question on here that I found,...

### Can one voltage output from OpAmp read with two ADC inputs?

this might be a little silly question, but please advise me. I am trying to use two photodiodes (one for the absorbance measurement and one for the source of the light as a reference) and the voltage ...

### Measuring Non idealities in an op-amp

First time poster: I want to learn about opamps. I am just a college graduate with no practical experience. What I know: A few basic high level applications such as Hysteresis, Voltage ...

### -1 Electronic MG87FE52AE DISPLAY SUPPORT [on hold]

According to subject i am using MG87FE52AE this ic to weighing scale PCB so i wanted extra display from the board. And that board have 6digit 7segment 16pin so i wanted to convert 16pin to 6 pin by ...

### Turning off op amp for low power application high side or low side

1 answers, 57 views op-amp analog floating
I have a design where I am using a LM324 to act as a buffer (unity gain impedence transformation amplifier) to feed the voltage from several high-impendence voltage dividers into my MCU's ADC pins. ...

### High freq. response of op amp using Miller

1 answers, 161 views op-amp frequency-response
I am trying to find the -3dB freq. denoted \$f_H\$ in the following circuit, where \$R\$ has been replaced with a capacitor \$C\$. I tried doing that in two ways which yielded different results. I'd ...

### splitter design

1 answers, 37 views op-amp buffering
I want to split the signal from my electric guitar to 6 amplifiers. Does this splitter design look legit? I want to use 6 fet op amp followers to do it. R2 - R7 are 47R to prevent oscillations (they'...

### -10 Day and night automatic switch [on hold]

simulate this circuit – Schematic created using CircuitLab I use LM741 as a comprater for solar day and night automatic switch but the output is low that is on 9v what is the problem in my ckt ...

### 1 Q: How to analyze Precision rectifier op amp configuration

I been scratching my head for the past couple of hours, and might be going mad. If someone can shine some light on this I would be extremely happy. This is probably root elementary to some but I am ...

### I need a circuit for a linear integrator using a capacitance multiplier

1 answers, 43 views op-amp capacitance linear integrator
There are various circuit topologies for capacitance multipliers using op-amps. I need to implement a linear integrator where it would be advantageous to reduce the size of the integrating capacitor ...

### What indicates a capacitor being charged or discharge in a circuit

1 answers, 73 views op-amp circuit-analysis
I am having troubles determining when a capacitor is being charged or being discharged, never understood the concept when a capacitor is under going that process besides the fact when a Source is ...

### Input impedance from RC filter to inverting and non inverting op amp

1 answers, 389 views op-amp filter active-filter
I am building a preamp for a sinusoidal current source. I have a two stage amplification process, with a bandpass RC filter in the middle. The second stage amplification is has two outputs from an ...

### 3 CMRR test methodology and effect of open loop gain

1 answers, 307 views op-amp test
I am trying to test the CMRR of opamp and so measuring offset variation across Common mode range in unity gain mode. I have gone through many articles on CMRR measurement. All those are suggesting a ...

### 8 How to properly use an op-amp?

ever since posting here I never been so lost of using op-amps before, hearing new things that I have never heard before (Vom, Vcm etc). I always thought OP AMPS is just plug it in and it will work ...

### op amp adjustable ramp generator

I traced this circuit from Induction Motor soft starter. My question is 1) What is the function of Q5 & Q6? 2) How the integrator opamp pin 5,6,7 works, which transistor is used to reset the cap? ...

### How to map 0.40-1.87V to 0-5V? [on hold]

1 answers, 85 views op-amp amplifier dc
I cannot seem to wrap my head around this. I have read about using an instrumentation amplifier, however even then I am not sure how to use this in this scenario. Could someone explain to me how to: ...

### 1 Role of the diode in the non-inverting op-amp circuit

1 answers, 62 views op-amp capacitor

### Multisim, Simulation Error

As the picture describes, the Vout is the division's result, but we have an error. Because my experience with MultiSim is not at a high level, why does this happen? Is this my fault ? ]1

### Current Measure on 230V 50Hz

1 answers, 175 views arduino op-amp current-measurement mains
I want to make a power meter which I can plug in a electrical socket in my house. I tried around with falstad to measure the current over a shunt and came up with this solution. But the problem is ...

### 2 Does the Sallen-key filter require a buffer for low power applications?

5 answers, 85 views op-amp filter buffer sallen-key
I am designing a circuit which takes an 3uV at 10-10kHz input that filters, applies gain and integrates the analogue signal. I'm thinking of using the circuit below for the topology using two stages ...

### Photodiode scintillation detector for gamma spectroscopy

1 answers, 50 views op-amp amplifier photodiode physics
I'm trying to build a basic detector for x-ray or low energy gamma spectroscopy. I have a big photodiode with a CsI(Tl) scintillation crystal glued on top (Hamamatsu S8559 for x-ray detection [1]) and ...

### photodiode circuit setup

2 answers, 400 views arduino op-amp photodiode
I'm working on a spectrophotometer for a physics project. I've figured out the monochromator already, so for the detector I decided to try a photodiode circuit. This being my first experience with ...

### Choosing resistor and capacitor for active filter

I am new in designing the active filters though I designed Active low, high and bandpass and notch filter successfully (using Opamp, R and C). But these filters are not actually designed by me :-( I ...

### 3 Constant controlled power source

5 answers, 352 views power-supply op-amp analog circuit-design
There are circuits for constant controlled voltage, and constant controlled current as shown below: Voltage controlled constant current source Voltage controlled constant voltage source simulate ...

### 4 Differential amplifier offset problem

I have breadboarded a simple differential amplifier: http://www.ti.com/lit/ds/symlink/lm158-n.pdf what I expect is that OUT=B-A but that only works when the voltage of B is larger than A+0.6, i:e ...

### -1 Confusion regarding this Op-Amp circuit

7 answers, 141 views op-amp amplifier semiconductors
So I have started learning about Operational Amplifiers. In case of idea Op-Amps, Vd=0 as amplification is very large and Vo is limited by Vcc(the supply voltage). Here in this inverting Op-Amp ...