Questions tagged [resistors]

A resistor obeys Ohm's law (V=IR); the current through it is equal to the voltage across it divided by the resistance (equivalently \$I=\frac{V}{R}\$)

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4
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4answers
182 views

How does one know that the current is flowing downwards through the \$8 \ \Omega\$ resistor?

I'm currently studying the textbook Fundamentals of Electric Circuits, 7th edition, by Charles Alexander and Matthew Sadiku. Chapter 1.7 Problem Solving gives the following example: Example 1.10 ...
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1answer
393 views

Find potential difference between nodes A and B in circuit below

By KVL and KCL Ix = 4A and Iy=Iz=6A The potential difference between A and B = Va - Vb = 6 +8Ix =38V I don't understand how we calculated the potential difference using KVL and KCL
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2answers
4k views

Ri and Ro - What do these acronyms mean?

I am trying to make sense of the below circuit diagram. What do Ri and Ro mean? What purpose do the resistors after the Pinouts of Pin 3 and Pin 2 serve? This is the datasheet for the sensor: ...
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2answers
297 views

Is there such a thing as an automatic variable resistor

I have a skid steer loader that in ISO eg driving straight forward with one joystick supplies on average 50 milliamps more power to the right forward solenoid coil than to the left coil causing the ...
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5answers
1k views

Calculate Power Dissipation of 0ohm resistor

I have a 0 Ohm resistor here. Can someone tell me how the power dissipation will be calculated for this type of 0 ohm resistor. The part says it has a power rating of 0.1W. But, if we use either V ...
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1answer
29 views

What is the difference between LDA 210 and LDA 212?

Do you see any difference between LDA210 and LDA212? Can it be that a factory produces the same product with different names? LDA210 datasheet: link LDA212 datasheet: link Official comparison ...
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0answers
22 views

Calculating the change in output voltage as temperature changes the control feedback resistance

I am trying to calculate the new output voltage when the temperature changes the resistance of the feedback network which sets the output voltage. I have this circuit using the MCP16311/2 buck ...
-3
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2answers
93 views

How can I solve this opamp circuit?

I am designing an Analog Front-End circuit for an NTC Sensor which has 3 parts, the non inverting stage, the low pass filter, and goes to seeeduino. Basically the input voltage is 5Vcc and I need to ...
0
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1answer
91 views

Voltage issue on pull-up resistor

I have an I2C sensor circuit, 3.3V applied to SDA and SCL pin through 10k resistor. I2C communication is not working so I have measured the voltage drop across the 10k resistors. It drops 2.86V and ...
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0answers
42 views

SMPS power supply - fuse resistor calculation

I'm designing a TNY288-based SMPS. My transformer input inductance is 931μH. I'm using a 320V MOV and have a doubt about the fusible resistor calculation. The output load is 12W, the input capacitor ...
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3answers
75 views

What size does my resistor have to be for the IC input?

I am testing some logic gate ICs to include in future projects. However, even when both of my switches are off, my logic IC is still sending a logical HIGH to my LED. I think my problem is the same as ...
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0answers
15 views

Source Transformation Finding TEC

I have been trying to find the thevenin equivalent circuit with respect to nodes a and b using source transformation. I end up having this setup. What would possibly be the next step I should do? Can ...
0
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1answer
55 views

My light-dependent resistor gives a fluctuating serial output

I'm a high school student trying to make a light tracking single axis solar panel. I am using an Arduino Uno rev3 board. When I first finished building it, the system failed to operate. I spent a few ...
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0answers
52 views

Resistor identification of crock pot

I'm having a problem with my crock-pot: the device turns on, but when selecting anything, it just turns off. Opened it up, and found the pictures below. I think resistor R49 is the problem - but since ...
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0answers
37 views

Are 4N35 optocoupler clamped at 22V?

I am trying to detect mains with an ESP32, for that I started testing this circuit: I bought a 4N35 optocoupler and 110kΩ resistors. My first test was using 2 resistors in serie, so R1 = 220kΩ The ...
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1answer
53 views

What is the difference between making a resistor based keypad and not using a resistor on arduino? [closed]

I've seen videos on youtube about how to emulate a keypad on arduino. Some of them includes a resistor while others do not. What are the difference between them and are there advantages in doing one ...
41
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8answers
64k views

What is a pull up and pull down?

Can some one explain this terminology please I think I understand it but not completely sure. I think pull down is where you place a resistor between +V and the other component and pull up is where ...
5
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4answers
573 views

Averaging thermistor readings

I have 9 thermistors arranged in a grid, and I want to average the readings from these thermistors without code (that is, average them in a circuit rather than reading all the values into a ...
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1answer
349 views

Control PTC heater with mosfet

I'm building an indoor greenhouse, I have gather a few tutorials on how to achieve what I need but on the heater I bought I can't seem to find anything that could help, and my knowledge on electricity ...
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2answers
206 views

Disconnecting a resistor out of parallel with a switch

I'm modifying an existing circuit. In order to perform this modification, I need to tap a resistor in the circuit and put another in parallel. By connecting this resistor in parallel (changing the ...
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1answer
2k views

Lowering resistance of potentiometer?

I saw a video where a person wired a resistor to the outer pins of a potentiometer to lower the resistance. Does this work? And if it does, can I still use the wiper and an outer pin with it lowered? ...
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9answers
3k views

What is the correct supply voltage for LEDs?

I have a 5V supply power, three 5mm red LEDs, and each LED has 47-ohm resistor. Two LEDs are bright but soon as I connect the third one all of them become dim. Where am I going wrong? I'm new so a ...
4
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1answer
608 views

Resistor values on a 12v 10a circuit with LT3045 LDO

I am currently working on a project that aims to provide 12v 10a in the final output. I am quite new to EE and wasn't quite sure if I have choose the correct resistors value as highlighted in the ...
4
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1answer
840 views

Why does this resistor not exist?

I have a 5W 5-banded resistor that shouldn't exist according to the color code chart and I've never come across this before. The color bands are brown, green, silver, gold, black. Now looking at it in ...
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4answers
70 views

E Series: is there any place that explains it?

So I am doing a work on optimizing circuits, and I came to study the E series of components. I'm a bit confused and I cannot understand soem things: How do the tables of values (E3: 1.0, 2.2, 4.7) ...
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4answers
163 views

Resistor in my AC LED circuit gets fried

I have designed a dead simple LED circuit I calculated the required resistance to be (220-2)/0.02 = ~11k so I used 10k+1k resistors in series but for some reason, ...
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1answer
78 views

Parallel RC circuit differential equation for a mechanical engineer

For a mechanical engineering course in controls, I was asked to Write the differential equation, state equation, and transfer function for this circuit That's the full text of the problem, and the ...
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0answers
51 views

Reducing 12v to 5v with convertor

To start, I'm a complete layman on this topic. If I say something that sounds inaccurate please do correct me. I'm here to learn as much as I'm here to ask for help. I have a truck with aftermarket ...
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3answers
96 views

Can I reduce AC current to vent from from 3A to 2A?

I have a range/stove hood with a really strong and loud blower motor. It's so strong that when we moved into our small house, the inspector made me disable the highest 3 speeds/CFM fan levels (600CFM) ...
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0answers
103 views

Replace LED with resistor in Christmas light string

A rodent chewed up an LED socket on a 100 light, warm white 3.2 V light string. I want to replace the socket with a resistor to keep the string within its voltage and current parameters. What would be ...
0
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1answer
310 views

WS2812B first LED flickering Wemos D1 mini

I'm running 110 WS2812B LEDs with an Wemos D1 mini clone (AZDelivery) and the first LED flickers and won't even turn off but rather show red or green. I changed the data line cable several times, ...
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7answers
35k views

What is the purpose of a bias resistor?

Could someone explain what "bias" is. And why do some devices need an external bias resistor?
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2answers
740 views

Find the transfer function of the circuit if current I is the measured output

So there's this problem I am trying to solve: Consider a series RL circuit corrected to a DC voltage source and an on-off switch. Assume R = 2 ohms, and L = 1H, and applied voltage V = 10 volts. ...
0
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1answer
349 views

Drive in movie speaker via bluetooth and mini amp

I need some technical help that I believe a site like this could answer. I bought some drive-in movie speakers which I restored by cleaning up and replacing the old 4" drivers.The 2 drivers are 4&...
0
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1answer
69 views

Looking for help identifying a resistor value

A resistor has burnt out in my heat sealer. Can anyone help confirm the type? From what I can find online it seems to be a 89G Ohm - is this correct? The body is 17 mm long.
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1answer
226 views

What component should I use? H-bridge? Relay?

I am working on a senior design project that involves regulating the noise from headphones to make sure no damage to the ear is done. I have all parts working except the part necessary to switch the ...
0
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2answers
58 views

Getting current and voltage on a resistor using simplification

I hope it's okay if I ask it here, but I've been playing with this current for quite some time now, and I've reached a dead end. I am supposed to find the amperage and voltage of a specific resistor (<...
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1answer
561 views

Leds in series with buzzer without resistor

So I'm pretty new at this, so I'm sorry for any dumb questions/statements. I'm trying to build a puzzle box where you activate a circuit with a reed switch using a hidden magnet. Activating this ...
3
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3answers
202 views

Resistive divider as resistors approach 0 ohms

Resistive divider when R1 = R2, split voltage in half because V = IR, and resistors in series add as Rtot = R1 + R2. It seems like this must break down as R1/2 approach 0 ohms. Anyone have a good ...
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2answers
81 views

How does a pull up resistor change a voltage divider calculation?

I am using this proximity sensor with a raspberry pi. the sensor outputs a 24V signal when triggered, which I need to step down to 3.3V using a voltage divider so as to not blow out the pi. The ...
2
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3answers
985 views

What are these components used for in the Arduino Nano?

What are the functions of the component(s) in the: red blue green circle? And what is a "+5V auto selector"? https://store.arduino.cc/products/arduino-nano
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2answers
61 views

Resistors max AC voltage datasheet

I want to make this circuit: Where Sens2 is mains (233VAC in Switzerland) I found this resistor that look perfect for the job: RND 155SP12 3W (datasheet). I don't understand what does max voltage ...
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1answer
549 views

Increase Measurement Distance of a Capacitive Proximity Sensor - Arduino Project

So I am working on a project that I found online at (https://makezine.com/projects/a-touchless-3d-tracking-interface/). However, instead of using my hand to track, I want to track an aluminum ball ...
0
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2answers
69 views

What type of resistor is needed for 5V 2A power? [duplicate]

I am new to electrical engineering. I need to power a control board that requires a 5V power supply. The instructions specify "5V 2A or 4A". I have a USB port that specifies a "max of ...
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2answers
82 views

Easiest way to make a resistor [closed]

What do I need to make a resistor of about 10 kΩ? After I make it, how do I measure the resistance with this device:
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6answers
2k views

Why do resistors "draw" current? [closed]

I was looking at an explanation for why parallel resistors have less resistance: Resistors in Parallel One of the answers involved simulating parallel resistors as a black box and it made sense. If ...
-2
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4answers
220 views

I'm new to circuit analysis and completely stumped on this circuit. Could someone please help me understand the steps to solve it? [closed]

I have to calculate the current and equivalent resistance but I don't even understand where to start. I'm not looking for a straight out answer I just want to know how I should go about solving it?
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0answers
102 views

Why would a common Gate MOSFET (instead of a resistor) reduce noise in a TIA?

simulate this circuit – Schematic created using CircuitLab I am reading a paper on TIA for optical receivers. On one of the improvements regarding the noise the writers replace the feedback ...
3
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1answer
112 views

Resistor between 74595 SRCLR and GND

What is the function of this resistor and is it okay with this value ? Rizki
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4answers
780 views

Differential equation for trivial RL series circuit

I would like to obtain differential equation describing behaviour of this circuit. I'm really new to this and not quite sure how to begin. We can consider situation of knowing values of all parameters ...

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