# Questions tagged [voltage-divider]

A voltage divider is a circuit that produces an output voltage that is proportional to the input voltage. One typical configuration consists of a pair of resistors in series from the input voltage to ground, with the output voltage taken from the junction of the resistors. As an example two equal valued resistors will give an output voltage 50% of the input.

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19 views

### CNY70 from 5V to 3.3V

I have CNY70 connected this way: And I need to determine the value of R2 for OUT to be from 0V to 3.3V. I don't know how to calculate it, please help. EDIT: Input is the 5V and output goes to ...
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I have a Hall element that I want to read by an ADC (MSP430 ADC10). The Hall element gives me a voltage within 0-Vcc, whereas the ADC can only sample 0-Vcc/2. In reality, the lowest value to sample is ...
96 views

### Can I feed my level shifter with a voltage divider?

I need to level shift 3V3 to 2V8. I have a 2V8 source but that'll require some patching wires on testpads and as such I would like to avoid it. I'm wondering: would it be safe to feed the SN74LVC245AN ...
66 views

### Cause a voltage drop of about 1V

I am currently working on a battery powered project (4 x AA rechargeable batteries) with an Attiny (max vin = 5.5V), which works perfectly so far. But if I would insert normal batteries into the ...
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### How to drop voltage to give a constant DC output

I have a load that drives current 1.8A[Max] @26V DC. It has to be supplied with a DC voltage of 30V[max]. I have a DC voltage 36V coming from another Power Supply Unit. In order to supply a constant ...
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### Having trouble finding Vo/Vs

I'm having trouble of writing the nodal equation cause of the voltage divider If you could help I appreciate it
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### Can an electrostatic voltage be divided with very large resistors?

Is it possible to divide an electrostatic voltage from a Van de Graff generator or electrostatic generator with very large resistors?
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### Need to check ON or OFF state of a wire using non-invasive method

We have a GSM SMS alert system (mod bus) that needs a signal that a wire (any wire from 3-phase) has current (maximum 15 amperes in ON state) or not, so we can know if the system is ON or OFF. There ...
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### Finding phase of voltage divider

I have this AC voltage divider here wish I want to find the exit voltage of. What I've done is I've applied the voltage divider formula: $$V_{out} = \frac{Z_2}{Z_1 + Z_2} V_{in}$$ Now that I have got ...
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### Can I use a buffer on my bias voltage net?

I'm a french stompbox / bass guitar pedal hobbyist, probably very bad at designing them. I've been thinking about bias voltage nets for some time, and how inefficient they sometimes are. I've studied ...
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### Voltage divider with 2 Input [closed]

Can you help me solve the below circuit with formula, I have 2 voltage source for a voltage divider and what is the output voltage and can u elaborate with formula
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### AC divider circuit used to charge a capacitor

The following circuit uses a capacitive divider network along with a diode rectifier to charge a capacitor. I assumed that once C2 is charged to its maximum( calculated to be around 14mV) the diode ...
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### How can I make my voltage divider work?

I'm trying to read the voltage of the battery so I can simply calculate the battery status. I'm using a 8.4V battery (recharcable PP3) that I've meassured now to 5.57V. The circuit will die long ...
42 views

### What change should I make in my Lead Compensator circuit below to reduce the DC response? Vin be sine wave with variable frequency

I want to increase my cutoff frequency, Fc. As Fc=1/2piR*C, Should I reduce the value of either resistor or capacitor to increase my cutoff frequency?
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### Current at specific moment in bridge circuit

At the below circuit i need to calculate the current Iab at 300 μs,can i apply voltage division to get the voltage across the appropriate resistors(30KΩ and 120KΩ)and by applying ohms law finding the ...
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### LiPo Battery power monitoring with ESP-12E

I am using 3.7V LiPo battery and ESP-12E in this project. I need to monitor how much charge is there in the battery to help when battery falls below certain level and notify to charge it up again. I'...
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### Voltage divider with potentiometer - Failsafe

I have a voltage divider circuit producing a reference voltage as follows: Vref is the control voltage for a regulator, and Vmeasure the output voltage of the regulator, with Vref being regulated to ...
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### ESP32. - selecting resistors for voltage divider

I'm using an ESP32 with a 12V battery and solar panel. I've created a voltage divider for 0-15v (3.3v input to MCU at 15v at battery side). For that I used a 100kOhm , and 300kOhm to get a 0.3 ratio. ...
32 views

### Resistive AC voltage divider and phase

I built myself a power monitor a few years ago that works and I was trying to simplify mine by cutting out an expensive and hard to find 12V ac:ac adapter. I am familiar with a voltage divider and it'...
182 views

### Trying to interface with intercom / door phone system (Read 15 times)

I have a project idea where I want to interface with my intercom / door phone system. Its a proprietary system developed by SSS Siedle, and there is next to no documentation or research on how these ...
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### Light sensor connected to GPIO input of raspberry pi

I have created simple light dector. Schemea is below: Real circuit on breadboard: I have written code in python using GPIO library: ...
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### Reading +/- 12V with 3.3V micro

I have 3.3V micro and +/- 12V square wave input I need to measure. As my MCU can only read 0 to 3.3V, I would like to ask the best way to "translate" this +/-12V signal into 0 to 3.3V. I try to ...
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### Light detection by GPIO raspberry pi

I have a cirtuit which consists of Resistor, Photoresistor, PNP Transistor, Voltage supply from raspberry pi like on the schema below: Purpose of this circut is to detect light as a dawn detection ...
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### Help with a PNP Switch

simulate this circuit – Schematic created using CircuitLab I'm trying to design a simple switch for a electric valve. I'm using a 2N4033, and I'm providing 12.3V between the emitter and the ...
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### lowering voltage of high frequency signal

One of the parts I have is RAM (1.5V logic level). The hardware communicating with it, is at a 1.8V logic level. The RAM signals are sent quickly - around 350-450Mhz. So I am pretty sure I can't ...
51 views

### Too low voltage at the output of op-amp

I'm using MCP6231 as voltage follower exactly like in pic below. When voltage at non inverting input is at level of 1.5V the output has only 0.8V. I have put 100nF ceramic capacitor close to the ...
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### Does 12 V DC to +6 VDC and -6VDC with discrete components require conversion to AC?

I have a 12 volt battery and want to power a 741 Op Amp, but that requires + and - voltage supplies. Is there a more efficient way to give a + and - supply to the op amp from the battery without ...
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### Overheat from voltage dividing circuit?

I want to create a circuit that is capable of delivering 1V, 3A from a 5V, 3A power supply. To do this im using a voltage dividing circuit with a 1k ohm resistor (r1) and 220ohm resistor (r2). The ...
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### How to obtain R1 from MAX31740ATA+T equation?

How to obtain R1 from MAX31740ATA+T equation ? The equation:
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### Microcontroller power supply problem [duplicate]

I'm using an LM7805 regulator in my circuit to supply power for my microcontroller (Attiny 13) and another module. I have to decrease 5V voltage to 3.3V for the microcontroller so I use two resistors ...
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### 5V Crowbar circuit using LM431 not triggering

I'm designing a crowbar circuit to to blow a 1A fuse, when the voltage increases above 5V. I'm using an LM431 and using the design in Figure 20 in the LM431 datasheet. I designed and prototyped the ...
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### Circuit to generate few microvolt pulse signal from volts pulse signal

I need to create a circuit which converts a pulse to very low voltage pulse (micro volts). This circuit output goes to an amplifier circuit. Right now, I created a circuit using a voltage divider and ...
4k views

### Need to keep re-soldering SMD resistors on PCB

I made a PCB to scale a +-100V signal into a 0v to 3.3V signal that I could read using an ADC on a microcontroller(see link for idea.) I used this solder paste flux to help with the soldering. ...
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### Converting fuel level sender reading

I have a fuel level sender installed in my custom built car which supposedly should read ~50 Ohms when empty, and 2 Ohms when full. I've measured it 30 Ohms empty, but this could be because the arm/...
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### How is an incandescent light bulb used for gain stabilisation?

If a circuit like the Wien bridge oscillator below uses an incandescent bulb for automatic gain control, how does this actually vary the gain? I know that the resistance of the bulb increases as the ...
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### Very high resistance

I'm playing around with a very simple setup: 9V battery light diode voltage divider (R1 - three 1 kOhm resistors, R2 - one 1 kOhm resistor), which should give me roughly 3V for the diode The first ...
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### Voltage Divider Efficiency

Is it typically advisable to use a voltage divider when trying to achieve a specific voltage in a power supply? I have a 15W +/-12V power supply and I need 10V, so what are the drawbacks of using a ...
87 views

### Equation to calculate voltage divider resistor value for an input of op-amp

I found this guide for a temperature sensing circuit design with NTC thermistor by Texas Instruments. According to my opinion, optimum R1 value is calculated so that the voltage divider can provide ...
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### Why or how would a volume pot work if connected in reverse, and how to simulate it?

I've come across a way to connect a regular pot to be used as a volume or gain pot, but the input and output terminals are reversed. It seems that this way of using it is somewhat common in the ...
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### voltage divider to drive bulb

I have some bulbs like this. Which takes about 3.8V, 0.3A current. Now I wanted to drive 21 bulbs in parallel. But i have only 12V voltage source. So I decided to use a voltage divider . when I ...
51 views

### How does Impedance matching equation work out from original link?

From this link: L-Pad Impedance Matching Equation How do you get those two equations? They do not look like a voltage divider formula, do they? Questions repeated here: First answer from Adil ...
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### The overall voltage gain in the circuit is not matching my simulation result. What am I doing wrong?

The overall voltage gain in the circuit is not matching my simulation result, but all other calculations of the circuit is almost the same. What am I doing wrong?
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### Using voltage regulators for a computer harddrive

I've got an Intel NUC (NUC8I3BEH3) that's using its own 19V, 90w power supply (pictures). After a few issues with 4TB 2.5" hard drives, and external USB disks, I'd like to use a 3.5" drive, but the ...
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### Calculate op-amp input voltage with potential divider and series resistor

I have managed to confuse myself when it comes to calculating the voltage drop over a series resistor connected to a potential divider (See below): The op amp non-inverting input is connected to a ...
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### How do I find the mode of operation of a BJT circuit without a value for Beta? Is there some trick to this question?

I tried finding the Thevenin equivalent of the input loop by using voltage divider to find Vb and Rb. And using Kirchoff's Voltage law on the input loop. But I'm stuck because there is no value for ...
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### Can you power a 3.3 led with an arduino 5v output?

I have a led that can handle 10 milliamps at 3.3v. Can I use a voltage divider and a plus resistor to power it from an arduino nano 5v digital pin? Maybe something like this. simulate this circuit &...
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### DC offset for AC signal

Hi guys, I am looking for some clarification regarding how to create a DC offset for an AC signal. Attached to this post is a quick schematic that I have drawn. Am I correct in saying that by ...
2k views

### Trouble understanding when voltages get split

I am having trouble solving this Op-Amp problem. I'm looking for Vo, and am confused as what to do with the 9V supply and the 2k and 6k resistors. Would the 9V be split between these two resistors? ...
I'm trying to get the value of $V_o$ in this circuit. Here's the circuit: Using Superposition theorem: So first, we remove the voltage source and replace it with a short circuit. Then we calculate ...