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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Vds Voltage of Nmos transistor at Lineer Region

I know the conditions for mosfet Id equations in saturation, linear or cutoff mode. For this circut, how can we find the Vds voltage when we know only values of the resistors and Vdd at linear mode? ...
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2answers
56 views

Linear voltage controlled resistor divider

I'm working on an audio amplifier project and I'm trying sort out the solutions to certain problems. The problem that I most need to get solved is that I want to digitally control certain operations ...
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1answer
55 views

Voltage divider resistor power disipation [duplicate]

I am trying to create a power supply circuit for the ESP8266, using a voltage divider and a cellphone charger rated at 5V, 1A as power supply. I have resistors connected like this: The resistors ...
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1answer
81 views

Why is the voltage across collector and emitter pushing itself to 0.7 volts?

I designed a single stage transistor amplifier as shown in this schematic: I constructed this on a breadboard and applied the DC bias voltage to check the biasing conditions. Prior to this, I made ...
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4answers
196 views

converting 3.3v to 1.2v

I have a electrical problem that I hope to get some help with. Let me first start of by saying that I'm quite a noob in this field (I'm a IT guy), but I hope to learn something. The problem I have is ...
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1answer
42 views

How do you calculate the resistor value for a bicolor led

R4 and R5 have equal values. For both LEDs the forward voltage is 2V and the forward current is 30mA. I know how to calculate the correct resistor for a single LED. However in this case I am using a ...
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1answer
45 views

Voltage divider output / OP amp

I have a voltage divider, and the output goes to OP amp. This is from my schoolwork. -1 to +1 input | [R1] 1000 ohms | ---> output to op amp | [R2] 1000 ohms | 2v How do I calculate output that ...
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1answer
55 views

Is Voltage Divider a Noisy circuit?

I want to design a voltage divider circuit to bias an op amp, this circuit will be a part in another circuit to measure a biomedical signal. Is there a noise issue arises from using voltage divider ...
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2answers
31 views

The role of internal voltage source resistance in pulsed operation

I have a question regarding the role of the internal voltage source resistance in pulsed vs DC operation. Here is a sketch of the situation I imagine: simulate this circuit – Schematic ...
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2answers
79 views

Is voltage divider formula stated wrong everywhere?

Sample voltage divider circuit: simulate this circuit – Schematic created using CircuitLab In this circuit, \$Vout\$ is, by Ohm's Law: $$ Vin * \frac{R2}{R1+R2} $$ But this circuit, by ...
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1answer
69 views

Pull-up resistor causing unintentional voltage divider?

I'm trying to use the output of a comparator as the input of a schmitt trigger built with positive feedback on another comparator. Both have open collector outputs. When the two are not connected, ...
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3answers
75 views

voltage divider two unknown resistors

The circuit is made of a variable resistor of 10kΩ value and two fixed resistors R1 and R2 .The output voltage V0 should be variable from 2V to 9V, i have to calculate the values of the two fixed ...
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35 views

Neon lamps in parallel DC

I am making a nixie clock and wanting to use 2 neon lamps in parallel for each colon. However in my test circuit I can only get one to strike at a time. The supply voltage is 170Vdc in order to ...
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2answers
114 views

How are the resistor values R1 and R2 calculated for a transistor amplifier that has a voltage divider bias

Good day friends I am trying to analyse the working of transistor amplifiers with a prime goal of designing a good audio amplifier that does not produce much distortion in the output. I am ...
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2answers
80 views

Using 12v car battery to supply multiple “3.5v” devices

I'm trying to supply power to strings of LED lights for emergency lighting purposes with a 12v car battery. With the 12v supply I figured I could get 3 sets going at the same time. The power supply ...
1
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1answer
58 views

convert 3phase 220v into 3phase 165volt

I use a frequency converter which has an input of ONE phase 240 volt, 50hz. This device gives me output from 200-240volt, 0-500hz and THREE phase. The spindle motor I have needs input of 165 volt, up ...
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1answer
68 views

Why does inserting a resistance in the common of my scope probe cause it to pick up AC noise so much worse?

I'm poking at the inside of a USB oscilloscope, with the hope of modifying it so that the scope probe commons can be referenced to different voltages. When I use my USB oscilloscope to measure a 24V ...
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3answers
129 views

Confused with voltage divider

I'm confused with voltage divider..For the voltage going into Base, do I use the formula A or B to calculate? After searching some infos on google, I assume A is the right formula? What's confusing ...
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29 views

Best method to make a voltage driver for DAQ input

My DAQ cannot handle 12V so I want to scale it to 6V. But for some reason I cannot use resistor voltage divider method because I dont want the source to drive current. Because the source current is ...
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79 views

Increase voltage of signal by 0.6V

I am trying to fix a voltage drop issue. The cable I am using has a voltage drop of around 0.6 V this is then fed into a charger signal input and because of this drop it does not see the alternator ...
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1answer
109 views

How can I divide a variable voltage in half for a fan (variable load)? [closed]

I have a Peavey PV 2600 amplifier (1800W RMS) that I'm going to use in my home theater, but the 24V 80mm fan is much too loud and noisy. I want to replace it with a silent fan (Noctua NF-A8 PLX), ...
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0answers
83 views

Measuring Battery Voltage from Microcontroller using ADC

I am currently using a PIC16f1826 to try and measure the voltage of the 3.7v battery that is powering said microcontroller. From my understanding, the ADC can measure from 0v up to the reference ...
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1answer
90 views

Need help understanding how to calculate the R value for LD1117

I am really trying to understand how to use adjustable voltage regulators such as the LD1117 sold by sparkfun. I had a look at the datasheet they provide in the product page but it points me to a ...
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1answer
43 views

Not getting appropriate output voltage from the sensor circuit. Is the Flex sensor damaged or am I doing it wrong?

I want to interface a flex sensor to my PIC18F and I am facing some trouble doing so. The flex sensor is a resistance based sensor, so I am using a voltage divider circuit with the appropriate fixed ...
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2answers
81 views

DC Bias and Op Amp

simulate this circuit – Schematic created using CircuitLab I want to add a DC volatage of 1.25V to a sine wave signal. I am using a DC bias circuit with a voltage divider (R1=R2=100Kohm) ...
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1answer
81 views

Voltage regulation: I need 2x12V DC from 25V DC

I have this problem: i have an op amp, that is powered with +12v and -12v dc. Also, there is a ground connection at 0v. Yet, my power source has around 25v dc and the voltage point 'in the middle' is ...
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2answers
118 views

How do security alarm systems measure zone resistance?

Recent security alarm systems use EOL(R) or DEOL(R) to terminate the line of the zones. Question 1: What method is used to measure the resistance of a zone? I can think of two options: It measures ...
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34 views

Soil Moisture Sensor [VH400] Scale down max output 3v to 2.5v to ATmega32 ADC Input

I built a voltage divider network( divides by 1.2 using 20K and 100K SMD resistors ), the input source for this voltage divider is a sensor ( VH400 soil moisture sensor). After various experiments it ...
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1answer
56 views

Biasing an NMOS to get rid of \$V_{th}\$

So here's a common way of cancelling out the \$V_{th}\$ in an NMOS. Am I better of use a good quality zener (in series with a resistor) or stick with voltage divider R1 and R2 below. Assuming we can ...
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2answers
59 views

voltage divider and op amp

when ldr is in dark, all voltage drop is across the ldr, so how does voltage at inverting input becomes negative when it is supposed to be 0V or (x)mV? and when ldr is in light, all voltage drop is ...
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3answers
104 views

How to interpret negative voltage in this schematic?

I got the following schematic from a book. This schematic was shown during a discussion about loads in voltage divider which require negative voltage. Questions: The voltage value -25V at the ...
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148 views

Multiple voltage dividers

So I have this circuit. I've been trying to figure out Vout. I couldn't find a specific formula for this situation. Can anyone help me figure out the formula? Thank you.
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72 views

Kirchhoffs Law with 3 Voltage Sources

So I thought I knew what I was doing but, this 3rd voltage source is totally throwing me off. Any explanation is very much welcome. simulate this circuit – Schematic created using ...
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1answer
80 views

Finding output values in a circuit with a zener diode in parallel with a resistor

Find Vout for all possible values of Vin. In this problem, Vf is the forward voltage drop across the diode and Vr is the reverse voltage drop across the diode. (You must break the problem into 3 ...
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2answers
117 views

Transfer function for this transconductance op-amplifier

I used the summing-point constraint and KVL to get \$V_{R_1<<}=V_{\text{in}}\$. Followed by a voltage divider for the node left of \$R_L\$; yielding: ...
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2answers
67 views

Why can Ohm's law be used in a linear circuit with multiple equivalent resistors without being given current?

I'm exploring voltage dividers and am puzzled by the conclusion made by the YouTuber in this video: "If you apply Ohm's law, you find that 1 V spread across two equal-value resistors gives you 0.5 V ...
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1answer
188 views

74HC4051 multiplexing and voltage divider

I need a voltage source for an Arduino analogue input. I'm making a capacitive sensor with an NPN BC548B transistor. In the emitter, I connect the GND, in the collector, I connect the analog port of ...
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1answer
82 views

Voltage divider not functioning correctly

I have a Raspberry Pi connected to an MCP3002. It's power and Vref is taken from the Pi's 3.3V I also took a two 1M resistors to form a voltage divider on the 5V connection to create 2.5V. Then on ...
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211 views

Can we use 3.3V voltage divider circuit from 5V voltage regulator for (800ma load and 3.3v)?

I am using (lm2576) 5.0v regulator from 12v battery 2-amps for my raspberry pi. I want to use 3 LDR and 5 proximity IR sensor for my mini project. For all sensor I need only 3.3V voltage. It is ...
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2answers
186 views

Some Basics of a Potentiometer?

This is my first DIY wiring project, I'm taking an RGB LED and using four potentiometers to control (1) overall brightness, and (3) each color level. Wanted to make it simple. For my purposes, all ...
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1answer
44 views

NTC based voltage divider relative error

I'm making an analysis of the error introduced by two different resistors in a voltage divider (and taking the voltage out from the middle of two series resistors). I'm using this for an NTC reading, ...
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1answer
67 views

Voltage divider with pull up resistor

I'm trying to trigger a logic fall signal on my raspberry pin input which is set with a internal pullup resitor (on 3V). The input raw signal I have in actually a 0V which change to -5V during a ...
2
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1answer
71 views

Simulation measured voltage not matching calculations

Ok, so I have the following circuit: click here for simulation The source voltage is 5V. The voltage measured between A and B is 2.44V, which differs from what I get by calculating that same ...
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0answers
44 views

What is 'low' in this cct please?

I'm trying to work out how to switch some LED running lights I want to install OFF when my sidelights come on. I think I understand how the cct works and thought that by putting in a voltage divider ...
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0answers
92 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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1answer
187 views

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
543 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
114 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
234 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
43 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 ...