# Tagged Questions

108 views

### Amplify current and voltage to preserve battery

I'm wondering, is it possible to provide for example 5V/500mA from a single 1.2V battery and consuming only 50mAh from the battery by using a low input voltage boost converter and a power amplifier ? ...
56 views

### Customizing both voltage and amperage in a circuit

I intend to control a motor via H-bridge L6205N (PowerDIP20). H-bridge's logic input requirements are: High level logic input voltage: 2-7 V High level logic input current: 10 μΑ Motor's supply ...
89 views

### Voltage through resistor connected to positive terminal of op amp

I have done quite a bit of research on this but I cannot seem to find an example or an answer at all. If I connect a resistor to the positive terminal of an op amp, since no current flows from the ...
65 views

### Operational Amplifier multiplier

I have a question involving a couple problems in the following PDF: http://www.engr.colostate.edu/ECE103/FA13/homeworks/Homework6%20FA2013.pdf For convenience, I'll also post them below. As far as I ...
112 views

### Suggest a Rail-to-Rail OpAmp to Replace LM741

I have built a small amplifier circuit around two LM741 op-amps and have had to learn the hard way, as I usually do :), that the LM741 is not a rail-to-rail output op amp. I have a 0-3.26V input ...
92 views

### What is the effect of supply voltage asymmetry in opamp amplifier topologies?

What is the effect of a $\Delta V$ voltage shift in one of the supply voltage inputs of an opamp on its functional behavior? $\Delta V$ can be positive or negative. Suppose that, I'm designing a ...
46 views

I want to use AD811AN as high frequency amplifier. According to its datasheet , Its Absolute maximum V+ and V- are +18 and -18 and differential input voltage is +/-6 V. Most of the graphs in the ...
68 views

### inverting op-amp circuit

Why is -Vout equal to the voltage going through Rf? here is a link to a site which explains the inverting amplifier circuit but I couldn't understand why this is.
501 views

### Extracting the Square Root of a Voltage

I'm trying to discover a circuit that will produce a voltage which is some factor of the square root of the input voltage. I.e. $V_{out}(t) = K\sqrt{V_{in}(t)}$. The factor K is irrelevant. I ...
138 views

### How do I convert a signal of 3v to 2v to a signal of 0 to 5 v

I'm measuring input voltages between 2v and 3v (3v volts corresponds to a reading of 0 and 2v corresponds to a reading of 10,000) on the analogue in of my arduino. I would like to measure the voltage ...
469 views

### Op amp voltage regulator using N-Mosfet

I am trying to make a voltage regulator using an op-amp and a MOSFET: I'm really new to electronics. Why is $V_{DS}$ always so low ?
204 views

### 2 to 4 level converter in 8-QAM

i want to make 2 to 4 level converter for 8-QAM modulation, i'm going to use two digital input to get +/- voltage level, i want the output approximately like this,, when the input 00=-3 V , 01=-5 V ...
471 views

### threshold problem on a Schmitt trigger op amp

I have the Schmitt trigger op amp on the below diagram. (channel A & B refers the oscilloscope probes on the following figures). The resistor values are selected to set the trigger threshold as ...
110 views

### Tips for adding voltage op amp to equipment

I have a source that creates a smooth sine wave in the range ±100mV at 1-15Hz. Due to distances I need to amplify the signal to at least ±5V, and I should also maintain the shape of the signal if ...
1k views

### How do I calculate the gain of an op-amp summing amplifier?

So if I have a summing amplifier circuit like the one below: I know the Vin1, Vin2, and Vout value and the circuit is designed such that Vout = -(Vin1+2Vin2) but how do I calculate the gain? I know ...
327 views

### Nulling Offset Voltage [duplicate]

I am using a ua741 op-amp. My question is, how can I use a potentiometer to null the output offset voltage? I believe if I'm correct, that output offset voltage means the output voltage provided by ...
122 views

### Op Amp different supply voltage than signal voltage

I need to setup a differential op amp. The question I have is if the source signals (from the sensor) can have a differnt power supply than that powering the op-amp. The op amp will be sent to a ...
156 views

### What opamp characteristics for voltage reference

What opamp datasheet characteristics should i look for when choosing an op amp to proivide a reference voltage like in the following image?
261 views

### op-amp circuit to transform input signal

In this typical op amp circuit, how would I go about calculating the value of each component if I want to simply transform the input voltage range into another voltage range, e.g. when input voltage ...
207 views

### OP AMP amplifier [closed]

I am building a simple op amp amplifier circuit using IC LF351. I m using this circuit at very low voltages about 100mV. however the gain does not remain the same at this voltage. Like the theoretical ...
181 views

### Types of amplifier - what is the difference?

What is the difference between an open loop amplifier and a voltage follower (unity gain buffer)?
87 views

### Wingman Wheel with different power supply? [closed]

I have an old Wingman Formula Force running on 20V / 1.5A, and I've lost my original cord/power supply. I have 2 other supples in here, one with 12V / 2.5A Second is 22V / 1230mA (guessing that's the ...
7k views

### Analog voltage level conversion (level shift)

I have a joystick that puts out analog voltage somewhere between 1.5V and 3.5V. I want to transform this range of voltage to control a motor controller that takes analog voltage between 0V and 5V. ...
252 views

### Water Meter Monitoring

Working on a project where I am wanting to monitor water meter via a magnetic sensor which will detect the spinning magnetic disc. It's very similar to the project this person has accomplished: ...
553 views

### Minus Voltage & Ground

Sometimes i come across different notations in Op Amps. Sometimes they are fed by V and ground, sometimes +V and -V. I am confused. Does ground mean minus? Look at here: ...
2k views

### Postive input ==> Positive and Negative output

I was watching some tutorials on thesignalpath.com and came across something that I didn't quite understand (even after it was explained). toddrharrison August 21, 2011 at 6:29 PM Answer ...
413 views

### Applying an oscillation to a DC voltage?

I've lost a 555 IC that I had owned, so thought I'd make an relaxation oscillator for practise out of an operational amplifier: The example of the simulator I have been using creates a square wave ...
1k views

### Can I use a voltage divider and/or voltage follower to produce 1V from 9V for an op-amp oscillator?

For a circuit I'm building, I'm using an op-amp oscillator to generate a sine wave. The sine wave will have a maximum voltage of 1V and a minimum voltage of -1V. The circuit will be powered by a 9V ...
881 views

### Basic 741 Op Amp Question

I am trying to build a basic 2 input summing amplifier using radio shacks 741 op amp. I have a feeling I damaged my IC chip through my wacky experimentation's. But lets run through the math just in ...
1k views

### What is the purpose of this op amp?

I am trying to build a pH meter using the below circuit. I am trying to understand the function of Op Amp U1. As I understand it, the LM4140A-1.0 is a voltage reference outputting 1.024V, which is ...