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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 valued resistors will give an output voltage 50% of the input.

73 questions with no upvoted or accepted answers
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77 views

Filtering out everything below 12v on a car reverse light circuit

First of all I've like to mention that I'm by no means an electrical engineer. I'll try to explain what I mean with the title. I have installed a headunit which has an option for a reverse camera. ...
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1answer
78 views

Lowpass Filter and Attenuator

I am designing a circuit to power a brushed DC motor. The motor will be given 24VDC, modulated with PWM. I would like to have an analog voltage sense capability for use with my Atmel ATmega328P @ 3.3 ...
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529 views

Convert [-24V,24V] range analog signal to [0V,3.3V] range for ADC

I need to realize a circuit that converts an analog signal from [-24V,24V] to [0V,3.3V] before sending that signal to an ADC "MCP3208". I found the circuit in the picture below and it works perfectly ...
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46 views

Did I do something here that could have damaged my Arduino Mega2560?

I built a simple project here with a Mega2560. I wired up a TEA5767 FM tuner module via I2C. I tapped into it's line out pins, did some DC biasing and connected it to analog inputs of the Arduino, ...
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2answers
63 views

Dividing output voltage from a buck boost converter

I am a student in high school and have been working with buck boost converters. I currently have a buck boost converter that steps up 5V to about 58V. I created 3 voltage dividers that should step the ...
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2answers
104 views

Measuring battery voltage in PV scenario with MPPT charge controller with inverter

So I'm doing a PV project with wifi enabled statistics. I'd like to see the watts coming in and out and the battery charge level, estimated battery charge and discharge time. I'm designing PCB to ...
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52 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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213 views

Buck/boost output voltage manipulation via feedback node

I'm designing an emitter follower circuit attached to the feedback node of a Buck/Boost SMPS in order to pull current out of the node and subsequently increase the output voltage by varying a DAC ...
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1answer
106 views

Voltage divider network calculation

Hello I am troubleshooting a voltage divider circuit in which I know the output going to U28 pin 3 should be around 700mv. What I am measuring however is around 7.5v. How do I calculate the v out for ...
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1answer
108 views

Single Ended Precision Variable Amplitude Square Waves and Charge Injection

I love to hear any thoughts about a good break-before-make analog switch with low charge injection or even even better any thoughts on generating precision amplitude square waves in general. As to ...
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298 views

Voltage Drop Across Capacitor Driven with Square Wave

I was having a discussion with a colleague. Imagine a circuit with ideal components. The circuit is a capacitor divider (1uF and 1pF capacitors) with the midpoint being pulled down to GND by a 1Meg ...
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765 views

How to make a open-circuit cable fault detector?

There are projects like this one over here: Underground Cable Fault Distance Finder, which checks if a given line is short-ciruited with any of the other lines. The location of the fault is also ...
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398 views

V+, V- and GND - Getting started with virtual grounds

I've been happily playing around with TTL logic but have recently come across an Analog / Digital converter TSC7106 whilst tearing apart an old thermostat which has demanded V+, GND and ... V- :o I ...
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1answer
214 views

How do I trigger a MCP2200 / FT245RL chip

In my original post I thought I had this turkey nailed, sadly not :( I've got a pnp laser distance sensor and a Denkovi USB relay board. I'm planning on using the laser to trigger the IOs on the ...
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160 views

Arduino yielding different results when plugged to USB and not

I'm programming a control system for a motorbike powered by a 68V battery. From this battery I have a shunt resistor whose voltage is amplified by an op amp and fed into an analog pin of the MEGA2560, ...
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2k views

24V to 3.3V Level Shifter

this is my first post so please excuse me for incomplete or improper text. I am developing an interface board to connect ‘Converter control unit’ to HIL system. For this purpose I need to level shift ...
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192 views

Voltage Divider?

I am designing a piezo micropump driver that feeds into a piezo electric transducer that mists a liquid. Both of these designs have been testedindependently and now its time to integrate. BST of ...
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441 views

Can I use a capacitive divider to run an AC/DC converter from a higher voltage than its rating?

Suppose I have an AC/DC converter rated to run from 120-240VAC, and I want to run it off 480 VAC. I think I should be able to put two capacitors in series as a voltage divider, and run the converter ...
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633 views

Building a +/- 150V DC power supply

I'm trying to build a +/- 150V battery powered DC power supply variable power supply. I have two of these 150V nixie power supplies: http://desmith.net/NMdS/Electronics/NixiePSU.html And was ...
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309 views

Low current (~100ma) buck voltage converter simple, low cost options (48V to 12V)

I have 48V AC-DC power supply that I use to drive high power LED drivers. I also want to use the same 48V input to power a 12V fan and Arduino Pro Mini. Fan is rated at 0.25A but I could do without ...
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1answer
108 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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47 views

Stepping Down Logic Level of a Differential Signal

simulate this circuit – Schematic created using CircuitLab Suppose I have a unipolar, differential 24V signal, and I want to step it down for use with a 5V differential receiver (such as RS-422)...
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44 views

Modifying the volume pot in a stereo amplifier

This must be a rather basic question. I have stereo amplifier with a 30K potentiometer serving as a volume control pot (two of them ganged together, to be precise). The pot is connected as a classic ...
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85 views

Can someone please help me find the equivalent resistor of this circuit?

Well I have to find the equivalent resistor of these ones and I am having a hard time trying to find it so some help will be appreciated. Figure 1. Original schematic. simulate this circuit – ...
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2answers
30 views

current limiter after a voltage divider for op amp input

I am doing a two-stages amplifier for a very small signal (-+300uV), coming from a radar sensor. The following two images are taken from application notes. I know R2 and R3 are voltage divider. 2.5V ...
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1answer
56 views

Questions regarding voltage divider for micro controller sensing

I am beginner trying to develop two voltage sensors for attiny85 microcontroller. I have two separate voltage levels that I want to sense using the attiny. One of the voltage supply is 0V-5.5V and is ...
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2answers
49 views

RC filter with voltage divider

I know I have got a trivial question but I can't find a proper explanation on the internet. In the image below I know that the formula for the cutoff frequency is f = 1/(2*PI*(R1//R2)*C). One way to ...
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26 views

Battery monitoring using voltage divider circuit using 4 resistor

I want to measure the battery voltage using voltage divider on different ADC channel, as shown in image i have to used 4 resistor and generate 3V, 2V, and 1V from 4V battery. i want to measure all ...
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86 views

Amplifying Current Transformer AC voltage

I am using YHDC (SCT013) split-core current transformer (100A:50mA) for sensing 3-phase AC. I have connected a 33-ohm burden resistor to the current transformer and with the voltage divider circuit, I ...
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27 views

Measuring voltage on different grounds PV inverter

I'd like to create a voltage meter that can measure battery voltage and PV panel voltage. The only problem is that the PV input and Battery I/O doesn't share ground. I'm not sure if tying the grounds ...
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1answer
82 views

Dynamic voltage divider

I'm trying to build an ESC (electronic speed controller) for three phase brushless motor. I found some intresting circuits but I am trying to build something very easy to do, with mosfet and pc817 and ...
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69 views

How to get output of 12V from a 15V output without dropping the current

I am planning on using NI myDaq to power a motor and encoder which requires 12V, but myDaq outputs 15V. How can I reduce the voltage to 12V without dropping the current? I was planning on using a ...
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2answers
73 views

Voltage drop and voltage dividers

First, I'm not interested in numbers or the general math behind this. I know how to split voltage into some particular value(s). But what is actually going on? I get Kirchoff's Voltage Law, or at ...
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54 views

Effects of a voltage divider on an audio DAC

Background: I'm planning on using a TI TS5A22364 SPDT Switch with Negative Signaling to connect AGND to the Left and Right Channels of the TI PCM5102A Audio DAC when the DAC is powered down as an ...
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64 views

Power off detection circuit to close opened latching solenoid valve

The image above is referred from this SO link. My use case is the following: A latching solenoid valve, which would be run using 4 AA batteries (6V) Solenoid Valve (9 Ohm) operates at 6V under 40ms ...
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61 views

Does anyone know the UL standard related to resistors and isolation on AC mains?

I have a circuit that is attempting to measure AC line voltage 120-240V but I was told by the certification test lab that my voltage divider resistors would require an expensive 3 week soak test. The ...
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69 views

Finding the voltage of base Vb

I wanted to know if Vb in the trasistor in the photo is equal to the formula in red circle: Vb=R2*Vcc/(R1+R2)
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92 views

Buffered Voltage Divider VS Differential(Subtractor) Opamp

I'm trying to understand which one of these circuits is the best choice for measuring 400VDC signal using a microcontroller . But at first look circuit number 1 makes more sense since it is giving the ...
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73 views

Drive 433Mhz emitter and Attiny with two coin cells

I would like to detect when the postman put mail in my box, so I was thinking about a simple attiny with tilt sensor (which would wake up the attiny) and a 433 MHz emitter: The problem is that one ...
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1answer
80 views

Constant current circuit load and without load for voltage measurement?

How can I control the constant current block? What I need? I need to calculate voltage with constant current load (I = 100ma and after some time I need to calculate voltage without load (I = 0), for ...
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2answers
86 views

Driving a hobby stepper motor with an industrial PLC

I am working with an industrial PLC, the Beckhoff BX9000, with 24 V digital outputs. I am looking to drive a hobby stepper motor with Polulu's 'A4988 Stepper Motor Driver Carrier', which accepts logic ...
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48 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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3answers
221 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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1answer
58 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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1answer
74 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
920 views

Voltage divider to measure 12v battery with arduino low consumption

I want to measure 12v. Car battery with arduino. Three questions: Is the R1 and R2 the best values? The car battery can go from +10v. To +15v. How and what can I use to save power between the ...
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2answers
53 views

Charging my cellphone with a 18V DC source

I have received a 18V 2.5W photovoltaic panel and want to use it to either charge a cellphone (or even two at the same time) or power some Arduino projects. In both cases I need a 5V source, but mine ...
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148 views

Current limitation to capacitive voltage divider

For an AC capacitive voltage divider, I would think the amount of current that could come from the divider would be limited by the absolute size of the capacitors. The flow of current should be a ...
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100 views

Debugging implementation of low current battery monitor

I have tried to implement the circuit in this answer in order to measure the voltage of an external battery using an Arduino. However, I am not sure if I have wired it correctly. Here is the diagram: ...
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140 views

OpAmp or voltage divider

I want to measure battery level within my circuit with an ADC. I've been said to scale the voltage to Vcc and use it as Vref of the ADC. I've thought of two options for doing it: a voltage divider ...