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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.

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Are my calculations wrong for the capacitance?

In an earlier post i discussed about the effects of voltage derating on a capacitor. From here i measured the output with DC and AC applied to a highpass filter and found the cutoff frequency with the ...
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Voltage divider resistance/wattage sizing

I am working on a small project currently -- I recondition hybrid car battery packs with a grid charging system, and I am working on a voltage sensing circuit that's monitored and available via a ...
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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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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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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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Fuel sender - need something to convert ohms to volts?

I need to connect a cars fuel sender(ohms) to a analog input on a GPS tracker (volts) Here's the catch, in our tests most fuel senders we worked with seem to send the data as ohms/resistance However,...
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Battery Voltage Monitoring

I have designed a simple battery voltage monitoring circuit to monitor a 3.7V Li-Po battery. My microcontroller (ESP32) uses a 3.3V supply. simulate this circuit – Schematic created using ...
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50 views

Voltage divider and LED

I want to measure voltage presence when an LED lights up (i.e. the IC_Output goes LOW, LED is common anode). The -Ve of LED is ...
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51 views

Best way to shift automotive logic to Arduino TTL

My vehicle ignition switch voltage is 9V when the vehicle is not running. It is 6V when button is pressed. I need a way to convert this to TTL Arduino digital logic levels. I thought I could use a ...
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What is the purpose of diode in parallel with the resistor divider in MOSFET gate driving circuit

I have built several 200W AC dimmers using Microchip 8-bit CPU and the illustrated back-to-back MOSFET circuit. I have seen on Internet schematics with the D1 diode in parallel with the R1 resistor, ...
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How to combine a LPF and a Voltage divider?

I have to connect a 5V analog signal to a 3.3V MCU analog GPIO input as shown in the attached image. I wonder if its possible to combine the 2 blocks of voltage divider and RC-LPF into a single block? ...
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How can I calculate voltage drop on non resistors?

I understand that calculating voltage drop with two or more resistors in series is easy because we can apply ohms law and divide up the supply voltage relative to the resistance of each individual ...
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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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Change range of data acquisition system

I have a DAQ with many inputs that can measure within +-10 V, and I want to go up to +-30 V. Using a resistor voltage divider could be an option, but this lowers the input impedance. I would prefer ...
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What might be causing an op amp to fail in a voltage follower circuit?

I have the following super simple op amp circuit that makes use of the AZV321 single op amp (https://www.diodes.com/assets/Datasheets/AZV321.pdf) in order to balance the voltage on a pair of ...
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44 views

Proving the output voltage of a resistor ladder only with usage of currents

I got the following problem. I would like to prove the the output voltage \$U_{aus}\$ of the following system. I only want to prove it by using currents. So I don't want to use the formula for a ...
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Diode (LED) forward voltage in series and parallel

As a preface I am just a hobby electronics enthusiast and not an electrical engineering student, and I am just starting out at that, so these may be obvious answers for even a first year student. As ...
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PCB - Altium designer resistor voltage divider calculation [duplicate]

Good evening, I have a problem, I'm not really studying EE or know anything about EE, but I'm doing an optional course in PCB design, in my schematic document, I have a place (picture), where I have ...
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Getting weird resitance drops with an FSR and a raspi using a MCP30

I tried to create a weight detecting device, that detects when a heavy objects are placed on a table. Its supposed to work like this: The raspi keeps checking the recistance on the force sensing ...
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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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154 views

Why is a voltage divider used when reading analog sensors?

So when reading sensors (ping sensors/light/pressure/etc...) I notice they always use a voltage divider with resistors before running the input into the ADC input of a microcontroller. Why can't we ...
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Issue having 4-20 mA interface with ADS1115

I need to make a 4x 4-20mA measuring circuit with ads1115 (VDD = 5V) 4 channel 16bit ADC I set ads1115 PGA to 4.096 gain and set circuit as below. once I set this 32000 ADC levels--> 4.096V--> 0....
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1M Ohm Thermistor Circuit voltage drops not adding up

The circuit is wired as follows ...
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77 views

What is function of the resistor in series with bypass capacitor in npn transistor amplifier?

I am new to electronics and recently I was learning about npn transistor as an amplifier. I tried to build one in ltspice XVII. This is my circuit diagram: but the output was not as expected as ...
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126 views

Are there special rules for voltage division of a high speed clock?

High speed signals require special care in PCB layout to prevent high speed effects like ringing and overshoot. This obviously applies to clock signals as well. Provided that one has a high voltage ...
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84 views

Why not use the same size resistors for each stage in a Kevin-Varley divider?

I was thinking of building myself a Kevin-Varley divider as described for example in this article about a mini metrology lab in the March 1996 issue of Electronis Now by Conrad R. Hoffman. The normal ...
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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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Why is the source voltage 1/4 of the supply voltage applied to the drain in a voltage-divider JFET circuit?

According to a Junction Field Effect Transistor (JFET) article in ElectronicsTutorial, the voltage across the source resistance is equal to 1/4 the supply voltage applied to the drain/gate for a class ...
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70 views

Voltage divider to drop volume of one speaker by 1.5dB

I have a a balanced stereo audio source, being fed into a headphone amplifier. Both source and amplifier are connected via a pair of 3-pin XLR cables, one for each channel. The amplifier then outputs ...
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65 views

Would a voltage divider work to lower the output voltage in this case for this open collector chip?

I want to interface the output Vo of this chip to a trigger input of a DAQ device. Here below is the chip which is open collector output so There will be a resistor between Vcc and Vo: And the specs ...
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144 views

BJT AC Analysis using r_e model

This is a picture of a Common Emitter Voltage Divider bias and it is been modelled using a CCCS and a diode resistance using the r_e model. Now my doubt is that I get problem in finding the input ...
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937 views

Ways to power an Arduino from 24 VDC

I want to power an Arduino (Wemos D1 Mini) with 5 or 3.3 V from my garage door opener, which has 24 VDC available. As far as I understand, this can be solved in the following ways: Step down buck ...
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Voltage divider Vout not powering ESP8266 [duplicate]

I have an input voltage of 12V from my power supply and i need 6V to feed into the ESP8622. I was giving it all the 12V but the wifi module becomes increasingly hot with time and so i decided to have ...
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Loading effects of a signal source

I'm reading "The Art of Electronics" (3rd edition) by Paul Horowitz and Winfield Hill. In the 2nd chapter on BJT (page No. 79, section Emitter follower). The author says: ".. In general, the ...
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96 views

Simple way to avoid current draw on resistor divider sense?

This is a simple, but complicated question. I measure voltage on several lines, more than 3'000. The lines can be up to 100V. I only need to measure at certain time, and would like to avoid current ...
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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 ...
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What is wrong with this voltage shifter?

I need to do voltage shifting (3.3V Papilio FPGA <--> 5V RAM chip). Most of the pins are output 3.3V -> input 5V, and 3.3V qualifies as "high" to a 5V device, so I can connect them directly. The ...
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156 views

Why do designers use op-amps with fractional gains?

I often find designs like the following simulate this circuit – Schematic created using CircuitLab Where the gain is less than one (\$\ R_2/R_1 < 1\$) Why not simply use a resistive ...
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How can I isolate voltage dividers so they aren't interfered with by other parts of the circuit?

I have a small and very basic circuit that PWMs an RGB LED. It has a potentiometer to allow me to set brightness level for night time and a LDR that allows me to detect night time. I took some ...
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92 views

Invert Voltage 0-2V

I need to invert voltage from the one sensor. So the ting is that I have DC signal from sensor: 0%-100% range of 0V-2V I need: 0%-100% range of 2V-0V I have LM324 level indicator and it is showing ...
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52 views

What is the best approach to calculate the transfer function of this RC circuit?

I want to calculate the transfer function of the circuit below. I tried to calculate the equivalent impedance of each block and work my way with voltage dividers until I get to V3, but this method is ...
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109 views

Voltage Divider with low noise?

I'm working with a nano scale motion stage with high precision. To move the stage I supply Sinusoidal wave using (Agilent Keysight) function generator. This F-gen, goes as low as \$20mV_{pp}\$ in ...
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85 views

Help simply the resistor usage in this voltage summer and divider circuit

Can someone help simplify the resistor usage in this circuit? VS is a constant 5v supply. Flex is a variable voltage between 0 and 5v. The resistors above have been brute forced to achieve this ...
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1answer
63 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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120 views

Voltage divider with pull up resistors

I'm designing a peripheral circuit between a sensor (U1) and a MCU (U2). U1 has an open-drain output pin to indicate its status. This pin will be staying at either HIGH or LOW constantly (not ...
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292 views

Do voltage dividers waste battery?

I am attempting to make a battery powered alarm clock with an Arduino, and I would appreciate some help on the circuitry part. I am very inexperienced with electrical engineering. I am using a ...
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62 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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132 views

How to solve a a full wave rectifier with two diodes and a ground in the middle?

This is the problem I am trying to follow along with the solution but I don't understand what is happening, how do I handle the random ground in the middle?? is the node between d1 and d2 40Vpeek and ...
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79 views

Are resistor networks appropriate for voltage divider?

I need to make 9 voltage dividers in order to connect 9 resistive sensors to the analog inputs of an Arduino board. I was tempted to use a 10K resistor network to individually ground the inputs but ...
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Arduino: read different voltage values in a range from -12 to +12V

I would like to trigger different functions in Arduino related to the following voltage values: -12V, 0V, 6V, 9V, 12V (the range is from -12V to +12V). According to the value of the voltage read (-...