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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 ...

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Dynamic range of voltages for ADC input controlled by software

I'm trying to build an interface that can take the readings from level sensors and provide a small enough voltage that a 3.3V microcontroller can read. I've done this successfully using the following ...
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1answer
49 views

12V potentiometer

I am trying to control the power of a vacuum pump using a 10k potentiometer with 12v as its input source. I've tried wiring it (with the know facing you)with the first lead as ground, second one being ...
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79 views

Autoranging Ohmmeter

Note: before i explain my issue i would like to note that I am a beginner in electronics please pay attention to that when providing solutions and explanations. Thank you. I have succeeded at making ...
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1answer
43 views

Would a bridge rectifier allow to detect µs-scale pulses of either polarity

The incoming signal is ground-referenced and consists of short (a few µs each) pulses at >150V. The signal is at ground potential the rest of the time (the "duty cycle" is low), and is of low ...
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4answers
1k views

Measuring AC voltage without a transformer using a microcontroller

As I have no practice with AC voltages, I'm asking if the following circuit is reliable for measuring AC voltages about 110Vca and 220Vca 50Hz/60Hz. I have already made it with a small transformer. ...
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1answer
44 views

Measuring input voltage with 3.3V ADC MCU

I am designing my very first DC motor driver circuit. Right at the start, I want to be able to measure the input voltage to the system. The system supposed to work with external DC power supply from ...
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3answers
94 views

GPIO state of MCU (AVR) with no supply voltage

In general: what state do the GPIOs of a MCU (an AVR in my case) have when there is no supply voltage and the MCU is "off". Am I right that the pins are floating as there isn't any "reference" for the ...
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1answer
52 views

Active analog attenuation with OPA2340

I wish to have active analog attenuation circuit. Following this page, I got myself some OPA2340. I use the B-side to keep the numbering somewhat intact. I go with the design on Figure 16-2 (p. 14/...
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35 views

ac voltage added to dc base line

I began to read up on transistors, which led me to this post on electronics stackexchange. At the end of the original post, the question asks "the voltage at the base would be a sine wave with the DC ...
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1answer
64 views

Not getting expected voltage at LED

I recently picked up and arduino nano kit and messed around with all the simple projects. I dont have much EE experience besides those so I have a question that might be pretty basic. I am trying to ...
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1answer
64 views

Using a voltage divider with buried zener voltage reference

My plan in the below circuit was to use a voltage divider from a Max6225 2.5Vref, to get 2V and 1V from it in order to use the full 16bit bipolar scale of the ADS1115s, but I'm getting strange ...
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LIS3DH ADC reading 0 ~ 30v

LIS3DH accelerometer includes 3 auxiliary ADC (ADC0 ADC1 ADC2). but ADC channels are able to read voltage 900mv to 1800mv which corresponds to (-32512 to 32512). but I would like to read voltage 0 ~ ...
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758 views

Simple Op-Amp setup for current sense has a strange working range

I am using a LM358D dual amplifier at the moment and my goal is to measure over-current on 2 motors. Before I'll be doing that, I made a test setup to test the equations and check the output signal of ...
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30 views

Voltage Divider for Comparator Threshold

I am trying to understand how the voltage on the negative pin of U2A of the below circuit is 1V/2.4V. From the author: "Threshold signal is 0V/5V but it changes ...
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2answers
52 views

Unable to start calculating this voltage divider

I'm trying to solve all kinds of voltage dividers for an upcomming exam, but I'm stuck in this one. I've solved it in LTSpice, but I cannot solve it on paper. LTSpice showed me, that the Ux=3V, but ...
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91 views

Deducing the value of a variable resistor in configurable voltage divider

Two variable resistors (RS & RE) and one static resistor (RC) are connected to a high impedance input analog input pin of a micro-controller. The static resistor is connected to ground and the two ...
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3answers
104 views

What is the best way to step my signal from 5V to 3V3? [duplicate]

I have some analogue signals between 0 and 5 Volts being fed from a multiplexer into another board that only accepts signals up to 3v3. What is the best way to step down the voltage? The signal ...
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4answers
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Creating required voltage across a device using basic electrical principles [duplicate]

Let me explain what I mean by an imaginary case. Let's imagine a 10 V battery in series with two resistors equal in resistance value. The voltage in between those resistors is 5V according to the ...
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2answers
93 views

How are voltage dividers used in circuits?

I am a newbie and wanted to understand in simple terms how a voltage divider maybe used to for instance, power 2 different LEDs of different voltages if they were within a circuit. The main issue ...
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1answer
97 views

Voltage divider which will work for low and high frequency signals

I am using the below circuit (fig1) to step down the voltage, which I found on the internet. I want this circuit to be operate properly from 1 kHz to 50 MHz. When the input is a square wave. But this ...
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1answer
53 views

Inconsistent DC Input Resistance in Black Box [closed]

How It's Measured I have a circuit (can be assumed as Black Box) I want to measure the input resistance (R2) at DC. I do the common method of using a signal (V1) with a known source resistance (R1) ...
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120 views

Voltage divider as supply voltage [duplicate]

Is voltage divider is a good option for supply voltage to an IC ? I am working with a 555 timer, MAX232 ,an Inverter SN74LVC and with a 12V relay. I heard that voltage devider is not a best way to ...
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1answer
87 views

Measuring 200 volts safely

While I can measure line voltage safely, I need to write a procedure to have someone else measure the voltage. The load is pure resistive,and I want to measure the voltage across it, with a battery ...
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1answer
65 views

Connecting an analog temperature sensor IC to an ADC input of a microcontroller

I am trying to connect an analog temperature sensor LMT84 (http://www.ti.com/product/lmt84) to a micro controller (3.3VDC) using its ADC pin which is 1.4V tolerant (max). My Vcc is 3.3V, ADC max ...
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4answers
71 views

Voltage Dividers for a beginner (with respect to soil moisture sensors)

I've just started with electronics and want to make an analogue soil moisture sensor (with Arduino). When I looked online for an explanation of the working, every site said that it works as a voltage ...
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1answer
21 views

Setting Over voltage and Under voltage limits for LTC4364

I am trying to set under voltage, over voltage and over voltage clamping limits in a circuit for Overvoltage Output Regulator with Reverse Current Protection using LTC4364 device. The LTC4364 uses an ...
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1answer
37 views

dividing voltage of shunt Vref Lm4040

the whole thing i'm trying to do for about 3 mounth's is measuring IR-level with high accuracy, i tried many newbie circuits with huge noises, unstable results etc.. then i focused on ADS1110, an ADC ...
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2answers
34 views

“mapping voltage” on an analog potentiometer using a voltage divider

I'm working on a simple project to learn electrical circuits. I built a little sound box that will play tones when you press buttons. The battery provides 3volts and the "power boost" is a buck ...
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4answers
125 views

Buck topology for a 3.3V to 1.1V for a SoC [duplicate]

I have been given this circuit in a design guide and it does not make sense for such a complicated circuit to be implemented just to get 1.1V out. It requires 3.3V (input) and will give 1.1V out. The ...
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3answers
77 views

OpAmp VS Voltage Divider VS Buck Converter (Current Sensor Output)

I'm working on part of a project and I need to build the circuit that reads the current through a phase of a motor using this IC from Allegro. Assuming there will be no more than 5A, and using a VCC=...
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2answers
44 views

1v for non-inverting op-amp input

I need to reduce 5v to 1v for use as a reference voltage in an op-amp. What would be the best way to do this? The simplest solution to me is to use a voltage divider, although I understand others ...
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1answer
37 views

Scaling signal voltage

I have a signal which toggles between 7v and 0v up to 100 million/sec. The receiving IC only accepts voltage levels up to 3.3v. What would be the best way to lower the voltage from 7 to 3.3? I ...
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2answers
90 views

Most efficient way to drive an LED from 9v source?

I have a circuit that I am powering from a 9v battery. I bought little 3mm flat LEDs and I want to use one for a power indicator, but don't want to use a voltage divider that will consume too much ...
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2answers
95 views

What should be the voltage divider resisor values in units?

I'm trying to build a circuit that lights up a LED when a battery connected to it is full charged. I found LM358 lying around so I plan to use it as a comparator. I want a 3.7v using a voltage divider,...
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1answer
55 views

Voltage divider with ac source

Left side of the voltage divider is a bit confusing. How would AC react with DC voltage? Considering a high frequency ac source, capacitor would act as a wire. So what will be the output voltage? ...
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3answers
136 views

step down voltage follower

I'm trying to create a circuit that will divide the input voltage in half, but still be able to supply a high current to the load. My input voltage varies from 10-15v and I want the output voltage ...
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3answers
102 views

How should I protect from overvoltage ADC?

I have a microcontroller with a built in ADC that I am using to read from an input pin (ATMEGA328P to be specific). I want to allow switching of resolutions on the input for our users (0-5V range, and ...
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3answers
123 views

Why is there a divider circuit here?

So I'm pretty new to electronics and just started playing around with the Arduino to learn the basics. In one of the projects there was just a simple button and 3 LEDs that are controlled by the ...
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1answer
86 views

The Art of Electronics 1.35

Forgive me if this is not the proper question format. Please critique it if not. I am new to this site. I am reading "The Art of Electronics" and cannot understand the jump made in equation 1.35 to ...
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1answer
83 views

Want to convert 14.8v to 5v at Max 30 Amp current draw

I want to convert 14.8v to 5v at Max 30 Amp current draw. IS this possible using resistors?? I don't know that how much current a resistors can draw without any circuit issue.
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1answer
73 views

slight voltage reduction

I am powering a circuit on 4 AA batteries. 6v is not going to hurt the circuit, but it runs more optimally at 5v. Is there a simple and effective way to drop the supply voltage by 1v to get the best ...
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2answers
31 views

Capacitive voltage divider with varactor

Is it possible to create a capacitive voltage divider where one of the capacitors is a varactor whose capacitance can be manipulated/varied according to a signal? A varactor is a two port device; what ...
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1answer
56 views

How does the voltage divider model a voltage source in this transistor bias circuit?

I encountered a text which says that the leakage current Ico (or called Icbo) adds up to the signal current hence causes thermal runaway because it causes temperature to increase and it also increases ...
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67 views

Voltage divider with negative voltage

I have a question regarding voltage dividers when dealing with a negative voltage. I will be connecting a MCP3208 to a raspberry pi zero W. I Plan to use the pi to poll the ADC every few seconds and ...
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1answer
81 views

How does this circuit works ? Usart level shift

I'd like to ask how does this circuit works: I understand how it works in principle, but not technically. It's a USART voltage level shifter. It's supposed to divide 5V to 3.3V by a resistor divider, ...
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2answers
61 views

Voltage drop using resistor divider for ADC sensing

I am using a micro controller (TI CC3220 - http://www.ti.com/lit/ds/symlink/cc3220.pdf) which uses 3.3VDC for its operation and has an ADC input range of 1.4VDC. Questions In order to use the ADC ...
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37 views

Need fast and exact voltage follower or divider cascade

Intro: I'm designing a makeshift oscilloscope and now need an input cascade for it (it is more fun project for me, rather than industrial-grade tool). The matter is I want to get something faster ...
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1answer
127 views

What kind of diodes are these?

I think they are tvs diodes but i can't find what type they are.
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2answers
155 views

What's the name of this circuit?

As i said in the title what's the name of that circuit and any characteristic for it?
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4answers
84 views

Strange behavior of voltage divider

I am using a voltage divider to supply a voltage to a system (I don't know what sort of circuit I am supplying the signal to, except it's used to drive a very large motor. It needs a 0-5v signal). ...