Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

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 that is 50% of the input voltage.

Detailed explanation of a voltage divider.

Reoccurring questions

Once in a while a novice tries to use a voltage divider to lower a *supply* voltage. Here are some threads which explain why that's not a good idea: - http://electronics.stackexchange.com/questions/106718/when-would-i-use-a-voltage-regulator-vs-voltage-divider - http://electronics.stackexchange.com/questions/75448/how-to-reduce-dc-voltage-using-resistors
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How to choose value of resistor in voltage divider?

I understand that the output voltage is determined by the ratio between the two resistor values, and that if the both resistors are same then output voltage will be exactly same for all; but what's the basis of picking the resistor values?there is…
Coldblackice
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When would I use a voltage regulator vs a voltage divider?

When would you use a voltage regulator vs a resistor voltage divider? Are there any uses for which a resistor divider is particularly bad?
Pete
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What's the purpose of these two diodes in this circuit?

What's to point of using these two diodes? Can't you just replace them with a resistor?
Michael Koeppen
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MOSFET as a voltage controlled resistor

This question might be too localized, but I try. Is it possible to replace a variable resistor by a MOSFET, under conditions shown in the following schematic? If yes, can someone propose a MOSFET type or the required MOSFET parameters. simulate…
sergej
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Measure Lithium ion battery voltage (thus remaining capacity)

What I am working with: I am running my self-made Arduino board (in the sense that I use the Arduino bootloader and code editor) at 3.3V, and powered from a Lithium ion battery, which is USB-charged by a corresponding Microchip charger IC. What I am…
boardbite
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Why do we need a voltage divider when we get the same voltage at the output as the input?

I am using a voltage divider circuit of 100 Ω and 10 kΩ resistors, and using their output for the (IRF740) transistor's input. I'm trying to figure out why do the resistors have those specific values. It makes sense that if I use voltage divider, I…
Edi
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How make a dual +-12V supply from a 24V SMPS

I'm trying to power a home-made load cell transmitter using a 24V single SMPS. I need to make +12, 0 and -12 Volts that are capable of 50mA. I wish to power multiple channels of opamps and bridges. I don't have much budget and availability of…
Ohbhatt
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How can you turn perceived brightness (log scale) into a linear analog output using an LDR?

This question is not about how to make illuminance (in lux) a linear function of voltage! It's about linearly representing the human perception of brightness, which itself scales logarithmic to the unit lux and is not equal to lux. TL;DR: How can…
Niklas E.
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LTspice fails at a simple two-resistor voltage divider. How can I fix it?

During some simulations, I noticed some oddities and narrowed it down to the following problem: This is is simple voltage divider using two resistors. The four traces show: supply voltage current through R1. Everything is good so far the voltage…
tobalt
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Voltage Divider vs. Resistor in Series

What is the difference between having a voltage divider vs just using a resistor in series. So for example, I have an input voltage with 12V, and two resistors in a voltage divider, R1=10k, and R2=10k, so my voltage is evenly split to 6V. How is…
Amandeep Grewal
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Low current battery monitoring

I want to run a micro-controller from a 1S lipo through a 3V linear regulator. I need to measure the battery voltage however. The problem with using a voltage divider is that it would drain the battery over time which may or may not have protection…
s3c
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How does adding a current source and extra resistor to source follower improve its performance?

This question is similar to FET - Source follower utilizing current source to lower voltage offset, although I do not entirely understand the explanations, which is why I am posting my own question. As part of an electronics lab, I was asked to…
corgiworld
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Why should we need DAC ICs?

Please look at the schematic below. This is a very simple resistive adder that works fine with any standard ! (TTL,CMOS,...) or any arbitrary voltage that is fed into it. On the other hand as there is no active component in it, it is extremely fast.…
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Which one is better as voltage divider: resistive, capacitive , low pass filter,...?

There are different types of voltage attenuators for AC signals ( a short explanation is here). The most well known is a resistive one. Others like capacitive, inductive or low pass filters are available ( Low passes may include many designs…
Aug
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Output impedance of voltage divider?

When connecting a 10S LiPo (42V) to my ADC via a voltage divider, I began wondering how to calculate the output impedance of the divider. simulate this circuit – Schematic created using CircuitLab For example, what is the output impedance of the…
JimmyB
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