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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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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112 views
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How to calculate the induced voltage?

From the given diagram: Conductor(C) is the only movable part with given velocity (v), connected to a stationary terminals(top & bottom) and an exterior circuit with a load. Will current flow ...
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1answer
89 views

Need help understanding simple diode clamp & voltage divide combination

I am trying to understand Art of Electronics 2nd Edition page 50. The bit that I don't understand is that the impedance looking into the divider has to be small compared with with R (see first ...
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1answer
44 views

What is a good resistance value for voltage divider to measure LiPo voltage with Arduino

(Full disclosure: I'm a newbie.) I'm trying to measure my 4S lipo's cell voltages using an Arduino Mega. I know that I should use a voltage divider (actually, several of them) and I think I ...
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1answer
221 views

Reducing magnetic field span, effects on induced EMF/current?

A conductor of known volume (V) passes a uniform magnetic field(B)with a constant velocity (v) the conductor is a source of induced EMF, a power source to a circuit. The induced EMF can be calculated ...
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2answers
23 views

Cermet potentiometer temperature coefficients

I'm engineering a system that is temperature-sensitive, between ~-10-30C. I've moved to using cermet potentiometers because of their sub-200PPM/C temperature coefficients. If I wire such a pot with ...
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2answers
74 views

Is there a difference between voltage divider and attenuator?

I am thinking about using a voltage divider to scale down the signal by 2/3 (-1.76 dB) as the following circuit diagram: simulate this circuit – Schematic created using CircuitLab When I ...
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1answer
64 views

19.5V to 15V - what's the best way to lower the voltage?

The problem is: I've got a power supply capable of outputting 19.5V 4A. I need to lower the voltage to power up a laptop that requires 15V and 2A. Which way is the best to do it? Construct a voltage ...
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1answer
78 views

resistor drift via temp messing with ADC readings in voltage divider

I am voltage dividing 0 to 64 VDC down to 0 to 1.8 volts via a simple voltage divider. I am using 1% resistors. The problem is that the readings from the ADC in my beaglebone black seems to be ...
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3answers
369 views

Arduino Uno reading analog 24v DC signal

Disclaimer: Please be gentle - I'm a newbie with electronics. Overview I have a proprietary 24v DC analog sensor signal that I'm trying to interface with using a Arduino based microcontroller. The ...
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3answers
110 views

12V signal convert to 5V without interfere

I have Wiegand 26bit bus. DATA0 - GND = ~12.5V when idle DATA1 - GND = ~12.5V when idle I need some sort of scheme or something to convert 12V signal to 5V without interfere. I have few ...
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42 views

Automate 3DS Analog Stick Input with Arduino

I have a Arduino that can output 5v and 3v. I have a Nintendo 3DS that runs on 1.8v. I need the Arduino to send between 0 and 1.8v to the Nintendo 3DS Analog Stick to control it. Do I hook up two ...
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1answer
49 views

Solid State Relay Input Resistor

I have a set of solid state contactors that I want to turn on and off with 24v PLC outputs. That contactor takes 4.5 - 15V inputs ( Changing the relay to the 24v input model is not an option right ...
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2answers
153 views

How to adjust linear voltage regulator equivalent?

I'm attempting to build a linear voltage supply. (I'm not touching the mains yet.) My first thought was to use an adjustable linear voltage regulator. Unfortunately, I found that linear voltage ...
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1answer
92 views

MOSFET gate protection zener diode math .please help

My circuit's voltage input can range from 6V to 12.6V. I want to use a p-ch mosfet for reverse bias protection. However, the FET I want to use has a maximum VGS of +/- 8V, so I have to protect it in ...
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3answers
80 views

Can I use a voltage divider and a multiplier to power a 12V component from a 5V supply?

My idea was to use a the two points in a voltage divider circuit (5V and let's say 2.4V), feed those through a multiplier to power a 12V component. Is this possible? Any problems that may be ...
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1answer
35 views

Astable oscillator with voltage dividers as source voltage?

This is a part of a larger circuit, which will eventually become an SMPS. I can't even seem to get the oscillator to work. The output of the transformer is 12V The idea here is to supply each ...
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1answer
133 views

Measuring AC voltage (0.333vac max) using a 10 bit ADC on Atmel ATMEGA328

new to this so please be kind. want to measure AC current in domestic supplies using an atmel ATMEGA328P chip wit the best resolution possible I need to use the split core current transformer ...
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4answers
88 views

Low side high side NTC measurement

I am using 100k NTC from Murata (SMD, 0603 package) for temperature Measurement. I will drive NTC (MCU_Output) only when i need to measure the temperature. Which of the following options is better? ...
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0answers
131 views

How to measure AC voltage without a voltage divider using microcontroller

I have to measure AC voltage of the mains supply 180-220 VAC through a microcontroller. I have been wondering how to measure it without using a voltage divider. Since the resistance may wear out with ...
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1answer
93 views

Diode and Op Amp

Can you help me finding the expression of Vo(Vi) and graphing Vo(t)? I have simulated it in multisim but i can not understand when the diode passes current or not.
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2answers
99 views

Help with an OpAmp

I need to show that V= 5*V1 - V2 Can anyone give me a hint so that i can proceed with the resolution? Thanks!
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2answers
57 views

Measuring angle position of a pedal

I am developing a electronic throttle control system for FSAE, and by rules of FSAE, I need to have 2 or more potentiometers to measure the position of my pedal. I've decided to use a rotary pot both ...
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1answer
57 views

Voltage divider (phasor domain)

In the circuit below, I have to calculate \$V_u\$. simulate this circuit – Schematic created using CircuitLab By applying the voltage divider between the series resistances below, I get ...
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1answer
76 views

Calculate values of resistors [closed]

How to calculate values of R1, R2 and R3? R4 is a load 40 Ohms 300 mA. R3 is connected to ATMega8 output. hFE3 of DB136 and BD135 is 40
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1answer
113 views

Buck converter controlled by a BJT based astable multi-vibrator with zener-based feedback?

simulate this circuit – Schematic created using CircuitLab This is my rough sketch for a buck converter controlled by a BJT based astable multi-vibrator with zener-based feedback. Before ...
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3answers
47 views

Calculation of a voltage in a single mesh circuit

simulate this circuit – Schematic created using CircuitLab Why is \$v_{R_2}=(v_1-v_2)\frac{R_2}{R_1+R_2}\$ ? Could anybody show me this formula, please? \$(v_1-v_2)\$ is the voltage ...
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2answers
63 views

Voltage Divider, increasing resistor value for solar tracker

I am working on a solar tracking device based on arduino and I am using LDR's (Light Dependent Resistors) as voltage dividers. The wiring is similar to this: The problem I am facing is that the ...
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2answers
126 views

How to default logic high after a voltage divider?

I have a 5V logic pin coming in that I want to cut down to 3.3V. When the 5V pin is detached, however, I want the pin to default logic high (3.3V). How can I choose R_pu appropriately? V_in = 5V ...
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2answers
99 views

Working out current, voltage and resistance in a Bridge circuit?

This community is so helpful, my thanks go out to any comment I got with helpful advice. Here's another homework problem. I've tried working most of it out, but I have a feeling that I'll have to ...
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3answers
365 views

How to solve this resistive network using divider rules and ohms law

I have a homework problem I've been trying to solve. So far I think I'm using the right formulas for the calculations. I just need help finding: The total resistance of the circuit, finding Vab ...
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0answers
71 views

Voltage divider to measure battery voltage on Arduino [duplicate]

I am working on a 3V battery powered arduino project. I need to monitor the battery so that I could send a signal when battery is dying. At first it seemed tricky because the same voltage is being ...
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117 views

The purpose of voltage-dividers in op-amp feedback?

simulate this circuit – Schematic created using CircuitLab So, here we have a typical op-amp with negative feedback. The non-inverting input is at virtual-ground, and if the input is ...
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1answer
59 views

AD8222 single supply EMG

I am working with the AD8222 dual package instrumentation amplifier from Analog Devices. I want to build a compact EMG system so I am trying to use this chip since there are not a lot of dual IAs on ...
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1answer
66 views

What is the variation of ammeter reading with PQ

Honestly, this is a homework question. A screenshot of it is given below: Okay these are the things I have done in order to take the answer. First I calculate the equivalent resistance which ...
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2answers
222 views

Understanding Dividing Voltage

I am attempting to get an ESP8266 to read temp from an analog temp sensor (TMP36). The ESP is on the Adafruit HUZZAH ESP8266 breakout. The board has a single analog pin that I believe will allow me to ...
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1answer
71 views

My Tiny Comparator

I just can't seem to get this to work. simulate this circuit – Schematic created using CircuitLab The diodes were supposed to prevent this from going in "reverse-mode", should the ...
2
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1answer
123 views

JFET biasing problem

I tried solving this problem, however I feel like there's something missing, I am asked to bias a N-channel JFET with using this provided data: Idss= 12 [mA] VDD= 12 [V] VP = -5 [V] VDS=VDD/2 ...
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3answers
140 views

Simple Capacitor Charging Question

Right, I have a very simple circuit that I aim to use as a delay circuit, everything was going fine until I started to over think it all and now I have totally confused myself and it is slightly ...
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0answers
63 views

accuracy of a voltage divider

I have a unit under test My rectified voltage is form 0-100V and the current is 0A to 2A. I need to measure a voltage after a full wave bridge rectifier and step it down form 0-100V to 0-1V. Did a ...
2
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2answers
196 views

Can I use an op-amp in voltage follower configuration as variable voltage power supply?

I see that this works in theory, but I my gut feeling says there is a drawback or caveat of which I'm not aware. Basically what I want to achieve is described best by the circuit diagram below. ...
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1answer
109 views

Which one is the better way to feed analog input to my ADC?

I am planning to use an AD7730L analogue to digital converter (ADC) chip, with a quarter bridge circuit. Everything was on the track until I realised something, which indicated that things were ...
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4answers
97 views

Use GPIO to disable voltage divider

I'm using a voltage divider to read the battery level of a wireless sensor platform using STM32L151. I'm shooting to use 20k for R1 and 10k for R2, to be under the 50k limit of the MCU's ADC ...
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1answer
41 views

What current values are prone to noise?

I'm using voltage dividers to drop down from high voltages like 327V peak to 2.5V peak and read it with an ADC. (Also reading lower voltages like 5V from various sources, so the above was just an ...
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2answers
78 views

Reading a 1.2V-8.8V Signal into a 5V Arduino Input

An analog DC signal that ranges from 1.2V to 8.8V (from a thermocouple amplifier) is to be read from a input pin on the Arduino that reads 0V to 5V. Other that using a potential divider consisting of ...
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3answers
220 views

Fast 220v AC power failure detection

I'm building an AC-Detection circuit. I want to detect when the AC power has failed ASAP so that I can react very quickly. (like 1-3ms should be enough time) This was my first idea. It works in ...
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2answers
72 views

Voltage shift 5V to 3.3V for PIC16LF145x 3.3V I/O input, several approaches

For USB device detection I need a way to shift that VBUS 5V to 3.3V in order being able to connect it as I/O input pin. The input pin should be high as long as VBUS = 5V, and low as soon as VBUS = 0V. ...
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4answers
86 views

Voltage divider help

I am just getting into electronics and been reading about voltage dividers, I wanted to build one myself. I have built the below schematics on a breadboard and I am not getting the voltages I want. ...
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2answers
117 views

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 ...
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0answers
115 views

Voltage divider biasing circuit switch, which resistors should I use?

Goal: To turn on (open) a solenoid valve valve for irrigation when the soil moisture sensor reports a value below X% and shut it off (close) above X%. X should be able to be changed between say 20-80% ...