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 resisors 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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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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39 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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37 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 ...
4
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2answers
106 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
56 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
318 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
63 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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2answers
66 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
39 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
55 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
95 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
66 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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0answers
56 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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2answers
104 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
59 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
81 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
79 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
78 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
38 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
55 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
91 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
48 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
74 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
61 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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72 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% ...
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57 views

Use LM324AN as unity gain amplifier

I am trying to read the voltage coming out of a voltage divider with resistors that could go into the mega ohms on the ADC of my micro-controller. The impedance of the divider is too great for the ...
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3answers
67 views

Calculate resistors value in voltage divider

I have the following voltage divider circuit with a potentiomenter, and I need to find the value of the resistors. simulate this circuit – Schematic created using CircuitLab How can I ...
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1answer
75 views

Reducing the voltage into a speaker passively

Well not high power, low resistance. I have an unusual situation where I am directly driving speakers from an oscillating signal ( its not audio its more like a buzz ) I only have 2 inputs 12v ...
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2answers
53 views

Digital Voltmeter - TriColor LED Output

I'm very new to electronics and I wanted to start with something that would hopefully simple, but also useful. I'd like to make a circuit that can read a DC input voltage (between 9V and 20V) and ...
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2answers
85 views

Convert 3v solar cell to 1.5v

I recently bought a solar cell rated at 3v and 200mA dc to power a 1.5v dc motor that is used as an air pump for my aquarium.All the 1.5v solar cells available here have low ampere like 50mA or so. ...
0
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1answer
47 views

Control connectivity of resistors in voltage divider arrangement

I am building a device to measure the resistance of a resistor using a voltage divider. I added multiple resistors so that the range of the divider could be changed by switching to another ...
2
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1answer
40 views

Reading Flow Meters from Mic Port

I am attempting to read two hall-effect flow meters through the audio-in (mic) port of an Android device. I want to be able to read both flow meters independently. The audio-in port is a standard ...
2
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1answer
114 views

Ohmmeter not working as expected

I am trying to build a simple ohmmeter by creating a voltage divider and then using an analog pin on a PIC18F2550 to read the output voltage and determine the ohmic value of one of the resistors. I ...
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1answer
42 views

ADC Differential inputs

I am trying to feed a 5V signal to AD7705 which is a 16 bit ADC and expects differential inputs. Do I need to divide my 5V signal using bridge and then feed it to the ADC or can I use it as a single ...
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3answers
98 views

How to create precision reference 2.5 voltage

Can I create a precision reference voltage of 2.5V using 7805 regulator and ordinary resistors(10% error)/diodes or do I need to rely on specific reference voltage generator?
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3answers
114 views

Voltage shift from 5V to 3.3V

I'd like to use MX-05V 433MHz receiver together with a Raspberry Pi. The MX-05V operates on 5V, but the Raspberry Pi's inputs only allow 3.3V. So i need to shift the RX data output level from 5V to ...
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1answer
29 views

Current Regulation in LED Driver and PFC Circuit

Datasheet: http://diodes.com/datasheets/AL6562.pdf I am trying to understand how this IC works block by block and I am confused about over-voltage protection in the error amplifier - specifically ...
2
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3answers
378 views

Convert an audio signal to 0-5V using single supply op amp

I'm trying to capture an audio signal using an analog input of an Arduino Uno. The Arduino's analog input must be between 0-5V. I'd like to use a single power supply via an 9V battery, so I'm using a ...
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1answer
121 views

JFET voltage divider bias calculations

Hi im having some trouble with knowing how to perform calculations for \$I_D\$ in a simple JFET where it is biased by means of a voltage divider. I understand that use of the equation: $$I_D = ...
2
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3answers
93 views

Control 3.3V IC using Arduino?

I'm working with an IC that can't take more than 3.3V (+/- 0.2V), including on its I/O pins. I want to control it using Arduino, but its PIN's are 5V. Now I'm wondering if I can use PWM to archieve ...
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4answers
133 views

How does the resistance of the load affects a voltage divider?

Every explanation I've seen so far about voltage dividers, only consider the two main resistors (that do the "dividing"), and pretty much ignore what happens after ...
0
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2answers
102 views

How to regulate a 3.6 V battery to two power rails (3.3 V and 1.8 V)?

I have a 3.6 V battery from which I need two voltage rails, one that is 3.3 V and one that is 1.8 V. How should I design this circuit such that it is the most power efficient? Here is what I was ...
3
votes
3answers
537 views

What is the function of voltage divider in the below circuit?

Hello I am a beginner in electronics and eager to expand my knowledge in it. Earlier I was trying to build an Ultrasonic receiver using a transducer and some op amps. I ran searches in the Internet ...
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1answer
849 views

Clock divider circuit with flip D flip flop

I am using D flip flops in my clock divider circuit. I have started with one FF and moving up with the number of divisions I want to have in my clock. This is how I want my D ffs to work. Now I ...
1
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2answers
52 views

Particular current divider

Consider this circuit: simulate this circuit – Schematic created using CircuitLab (this part is preceeded and followed by other components). $$I_1 + I_2 = \displaystyle ...
0
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2answers
90 views

Alternative to V divider for high currents

I am looking for suggestions as to how to supply power to a gate drive optocoupler i am using. The supply being used is a 25V (rms) ac supply and intend to supply 10V DC at around 500mA+ from my ...
1
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5answers
109 views

A simple voltage divider

I attended a workshop on troubleshooting and we were asked to find the flaw in the given circuit. A guy pointed out to the organizer that R3 was short ckt and R2 was open ckt. However I was pretty ...
0
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3answers
71 views

Choosing the right voltage divider by load

I'm using an Android IOIO board to detect simple digital pulses from a 12v source. The input pins are 5V tolerant. Would a simple voltage divider work in this situation? I guess my concern is whether ...
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169 views

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.
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317 views

Sensing AC high voltage to microcontroller

I'd like to sense if I have AC 220V 50HZ available, and convert it to some logical level. I made such circuit, will it work? I use C1 as a resistor. Any recommendations what can be improved? ...