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 can I check that the voltage output from this voltage divider is 2.25V?

I was learning about voltage dividers from here, and I decided to try a test circuit with my Radioshack learning lab. With an input voltage of 4.5V and two 1000Ω resistors, I expected the voltage output would be 4.5*(1000/(1000+1000)) = 2.25V.…
DragonautX
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Upper limit for resistance values in voltage divider?

I am measuring the voltage of a 24 V battery using the ADC from Arduino Uno. I use a voltage divider to bring the voltage below 5V (the maximum the ADC can accept). I noticed that as long as the ratio of R1 and R2 is the same for my voltage divider…
Eiver
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Is voltage divider applicable on circuits where there is no ground?

For the circuit below, if the bottom terminal is -Vin and not grounded, is applying voltage divider possible at all? If this is the case, what would the equation be? I never heard of a voltage divider with no reference ground at the bottom.
Xiagua
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How can I rearrange the voltage divider formula for R2?

Can I please have a step by step explanation as to how I can rearrange the voltage divider formula to find R2. I dont understand how I end up with R2 = R1 x Vout/Vin - Vout.
ikram1ali
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Is voltage divider output affected by load resistance?

Very basic question. Assume a voltage divider where both divider resistors are equal value, i.e. 100K. If 48v is the applied voltage, it's easy to see that we'll measure 24v across the "load resistor". However, when we add a load in parallel with…
user35747
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Trouble with voltage divider and Wiegand reader

I'm attempting to use a 12 V Wiegand reader with a 3.3 V microcontroller. To drop the voltage from 12 V to a safer level for my microcontroller, I decided to employ a voltage divider. Specifically, I used a 10 kΩ resistor in series with a 3.3 kΩ…
Sandra
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Term similar to "gain" for voltage dividers

In amplifiers, the magnitude of amplification is called "gain". Is there an equivalent for that on how much a voltage divider divides? Like how a voltage divider with a 100k and 39k resistor has a "divide" of 0.2806. I wasn't able to google any…
HFOrangefish
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Voltage Dividers

I've just started design in electronics and am a student of Electrical Engineering. The questions that I have are the following: How many resistors can be used for a voltage divider configuration? Is it just two or can there be more than that? When…
user38559
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Voltage Divider-like circuit with multiple sources

I'm extremely new to circuits and am having some trouble with a variation on the voltage divider problems I've been doing. I'm trying to determine \$V_{out}\$ in the following circuit relative to some \$V_{GND}\$ that I need to determine the…
Henry H.
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Voltage Divider not functioning as expected

I've set up a voltage divider to take a 5V signal down to 3.3V. I'm using resistors with values of 6.8 kΩ and 3.78 kΩ. When I use a 5V source straight from a wall wart, the voltage divider works exactly like I would expect: I get 3.3V out of the…
WhiteHotLoveTiger
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600VDC measurement with Arduino (voltage divider)

I need to detect quick (~200ms) voltage drop, so I am thinking of making an oscilloscope with Arduino. Problem is - can I reliably read 600V DC voltage and what resistor values should I choose for voltage divider? Can I apply same rules as for lower…
Ri Di
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Why does the capacitor connection reduce into 110 V instead of 99 V?

I saw the following voltage divider on YouTube: Simple convert 220V to 110V And I saw it is a so-called voltage divider using capacitors: Capacitive Voltage Divider as an AC Voltage Divider And I thought to implement the following circuit: simulate…
Dimitrios Desyllas
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Why use a ten-percent rule-of-thumb for a bleeder current on a voltage divider?

A book I am reading recommends "The 10 Percent Rule" as a method for selecting resistors for a voltage divider: The book claims it is a standard method. My question is: why choose a bleeder current that is ten percent the load current? Why not…
Jordan
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Equal and opposite Voltages applied across 2 resistors of equal Value

Take a look at this picture here: Please note that the two resistors are equal in size. Here it says that the voltage at Point TP3 is zero volts. I do not understand how that is. The creator of this image says in a video that this is because the…
The Guest
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Why some circuits uses additional resistor with pot in dividers?

Are there any profits of using the first circuit for divider instead of the second one? simulate this circuit – Schematic created using CircuitLab
user54579
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