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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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47 views

Why using a 0 value resistor

In this schematic example they are using a 0 value resistor for R3 on the right side. Why should I do that? Is this only because of the TP? As I dropped the TP for my design I would think of dropping ...
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1answer
30 views

Does resistance depend on shape of conductor?

The area,length and material is same. Example a circular and square crosssection having same area
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0answers
32 views

Voltage and Current required to heat nitinol wire?

Dia of wire=0.5 mm; Length =200 mm;Transition Temperature=40 degree Celsius ; Wanted to know the voltage and current requirements to get a new shape. Will the circuitry require any resistance? I guess ...
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1answer
39 views

LCD contrast switcher for 8051

I'm trying to come up with a good circuit from common parts that will allow me to set predefined contrast levels to the LCD from the microcontroller. I've seen an example on the internet but its for ...
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1answer
47 views

Base resistor configurations, are there any differences?

Sorry for the noob question. From my understanding, R1s acts as pull down resistors for the base and R2 will limit the current flow to the base. I have seen both configurations, but couldn't work out ...
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2answers
88 views

Trying to solve a circuit containing 2 current sources and 1 voltage source and resistors: what am I doing wrong?

Here is the schematic and the values given. This is for a Coursera test on Linear Circuits I am taking and where I am stuck :-( Doing KCL and KVLs I get this: $$ \frac{V_a-V_b}{R_1}=I_1+i_B\\ i_A+...
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2answers
52 views

inline pull up/down resistor decrease resistance when encapsulated

I am working with a 500 MΩ resistor, assembled in the fiberglass tube with both ends closed. There is dielectric-silicon filled in between the resistor and fiberglass tube, which gets cured in 24 ...
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2answers
80 views

Please Critique my HV Measuring Setup

At the moment, I am working on a device that will be able to measure the out put of a high voltage DC power source with an adjustable output of 0 - -60 kVDC and 0-15 mA (the typical power being 600 ...
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3answers
87 views

Dropping 50VAC to 10VAC-20VAC

I am installing a Ring door bell. At the old intercom I have 50VAC currently (NO other source). According to the manufacturer I need between 8VAC and 24VAC. My question is what resistance (...
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3answers
78 views

Can I use a Dupont cable with a resistor soldered in the middle as a pullup resistor for I2C comms?

The short question: is there a difference between using (on a breadboard) a standard through-hole 10K pullup resistor, versus using a modded Dupont cable with a 10K pullup resistor soldered in the ...
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2answers
56 views

How to split up voltages

I want to power up bluetooth receiver module (input voltage 3.7) and audio amplifier module which accepts only 2.4 - 3.7 voltage, exceeding which already burnt the IC. So i got new one. I'm having 2 x ...
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3answers
103 views

I am trying to build a 0-42v Voltage measuring circuit that outputs to a 5v Micro! Failing badly

I am on to my next project which doesn't seem to be working as planned. At first I thought that I would find a boatload of pages on how to do this, but to my absolute surprise I couldn't find anything ...
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1answer
57 views

Value of 5-band resistor (current sense)

I have some blown current sense resistor and I don't know how to figure out the value of it. Resistor is blown so I cannot measure it. Well, I know about standard rules, unfortunately none I know ...
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4answers
100 views

What is the Gain, Input and Output Impedence in this circuit?

So I'm trying to know what the input, output impedence and gain is in this circuit To begin, I'm kind of confused since I don't know if those two resistors at the right are in series or in parallel.
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3answers
71 views

Wiring up a current limiting resistor with an IR LED burns of the LED

I have a 5V DC supply and i am trying to wire an IR led with a resistor in series to it. I have wired it up to a bread board as shown in the pic The current limiting resistor value is ~ 216 Ohm. ...
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1answer
77 views

Fusible resistor

I'm currently working on an assessment for the electronics part of my PEO and have to complete a resistor report, detailing different types of resistor and their circuit symbols. I have managed to ...
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1answer
50 views

Buffer OPAMP feedback resistor

I am using an LT1630 as a buffer... I know its not the greatest OPAMP for the job because it has fairly Hi input current, but It has good DC characteristic, HI current drive, and rail to rail ...
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1answer
68 views

LEDs to indicate Data being transferred

just asking for some reassurance really, probably a novice question. Thank you in advance for any advice. I am building this project: https://github.com/brianmarkpeters/CHIP_BASED_SYNTHESIZERS/tree/...
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1answer
48 views

RC-circuit with one input terminal and many outputs with different integration time

What is the simplest way to create an RC-integrator with one input terminal and several output terminals which differ their times of integration (see schematics below). simulate this circuit –...
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1answer
47 views

Doubt with current across several resistors (serie) and Resistor Power Rating

I have read that the current that flows across a circuit of several elements connected in serie is always the same but, as far as I understand, resistors consume current and disipates it in form of ...
1
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1answer
50 views

Can I sum up multiple, alternating series capacitors and resistors like this?

When the components are between each other, can I sum up multiple, alternating series capacitors and resistors like this? Thanks.
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1answer
78 views

Solve the ideal diode circuit

assume forward biased replace the diode with iD going down and short circuit it and make VD=0 combine 70Ω and 30Ω resistors that are parallel and it becomes 21Ω now 21Ω ...
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0answers
37 views

Use an NPN transistor for 12V logic

I want to steer this led strip: aliexpress link With my atmega. Since I will be connecting it to a car, the 12V power will be easily supplied from the OBD2 port directly, but I will need to send data ...
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0answers
57 views

Boosting speed of data on GPIO line between microcontrollers

I made a circuit in which the data bus P0 of an AT89S52 is connected to the P1 of an AT89C4051 and both clocks are each driven by their own 22.1184Mhz crystal. I have used a 10K standard pull-up on ...
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1answer
91 views

Correct wiring of a variable resistor

I built the following schematic and I made a mistake. I wired the 4.7M preset reversed. This is the original schematic: And this is the schematic that I drew in Kicad: I already built the PCB but ...
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2answers
66 views

Connecting Led in Series with Parallel Switches

I created a diagram for a circuit that i am trying to implement. I have attached my circuit diagram and have been trying to implement it but still have not got it to work. I've checked all the wiring ...
4
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2answers
442 views

Heating a box (as a thermodynamics dummy)

I expect to build a dehydrator and am knowledgeable enough for most of it (fan, timer, power supply and so on), bar the most important part: the heating element. If you're not familiar with electric ...
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2answers
97 views

Is a resistor required to power a LED strip with a 9V battery?

I have a 7020 white light LED strip, which includes a resistor on each module as you can see: I would like to power a little strip of five of these modules with a 9 V battery, but I wonder : 1- Do ...
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1answer
53 views

Building a series RLC circuit using a given resonant frequency and bandwidth value

Assuming that we have to build a simple series RLC circuit in such a way that the its resonant frequency must be 200 krad/s and its bandwidth as 20 krad/s, we have these components: Resistor: 1000 ...
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1answer
81 views

Increase headphone impedance using resistors

I have an LG-V30 cellphone, which has an integrated headphone amp with two modes for audio reproduction depending on the headphones you plug in. Normal mode for headphones under 50 ohm, low output, ...
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1answer
69 views

Problems with input leakage current in a microcontroller

I'm trying to build a system in which a microcontroller receives (through one of its input pins) a logic 1 if a switch is pressed and a logic 0 if it's not. For that purpose, I want to implement a ...
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1answer
150 views

Audio signal circuit. What is the 200 Ohm resistor doing in this circuit? REDRAWN

*I tried to draw this on the circuit drawer, it's excellent, but I didn't know the exact pieces to put in. Considering the trouble with my first drawing I thought it worse to use the wrong components ...
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2answers
43 views

What to use to crimp a resistor onto 18awg wire

I want to crimp a resistor like the one below onto 18awg wire without soldering... I've seen that bootlace ferrules like the photo below can possibly be used to do this but if I buy 22-24awg sized ...
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0answers
20 views

Lowest resistor value for enclosed light sensor unit with nearby lighting without losing sensitivity

This is a drawing I made of a light sensor unit I'm creating. Inside of it, I have a circuit board containing 3 7-segment displays and I have two photo-transistors (yellow half-circles in the picture) ...
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2answers
72 views

Exactly what type of resistor is being referred to in this diagram?

I'm trying to control an RGB LED strip using a NodeMCU. I have been following the guide linked here. However, the diagram included in the diagram is rather unclear, especially for someone like myself ...
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3answers
79 views

How to know when to tune up a digital multimeter?

I have bought the multimeter with temperature measurement from the following website: http://futurlec.com/Multimeters.shtml Currently I use the voltage, resistance, and short circuit detection ...
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1answer
47 views

Sensor range and speed based on resistor

I have 4 of these sensor circuits and can't quite figure out the optimal resistor value to use. Here's what I assume (which somewhere I may be wrong): The datasheet for the IC states leakage current ...
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2answers
68 views

Alternatives to High Wattage Resistors? (Do multiple low-wattage resistors equal a single higher wattage resistor?)

I am a beginner, so I may have made a horrible mistake in my diagram, but I am trying to learn. According as I have figured it, I am having an issue wherein I need a resistor rated for a minimum of ...
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2answers
85 views

Can I touch resistor connected to mains power? [closed]

Can I touch resistor connected to mains power? simulate this circuit – Schematic created using CircuitLab
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1answer
59 views

Is it possible to calculate the total resistance of this circuit with series and parallel analysis?

If I have a circuit like the one below, is it possible to determine the total resistance with the usual series and parallel analysis? I have been staring at it for a while and cannot see how I might ...
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1answer
34 views

Can I use a simple resistor for ESD protection on an ESP32?

This question applies both to digital and analog inputs on the various ESP32 dev kits. From what I can tell, none of these boards (including my OLIMEX-EVB and Gateway boards) add any ESD protection ...
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1answer
61 views

Log-Taper Variable Resistor from Linear-Taper

I'll start by saying: I've read quite a bit about how to make a "log taper potentiometer" using a resistor and linear-taper potentiometer, but I'm not sure if that will work in my case. I'm working ...
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2answers
113 views

What is this component called? [closed]

I recently bought an old coffee maker but it doesn't work. Everytime I switch it on my earth circuit breaker goes off so my whole house doesn't have electricity. I already looked on google to find ...
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1answer
40 views

Base resistor for BJT Transistor [duplicate]

I'd like to use PBSS4350SS transistors for driving multiple low power solenoids, but looking at the datasheet I can't figure out what value the base resistor (R1) should be? simulate this circuit &...
0
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1answer
47 views

Voltage (and possible resistor) required for electromagnet

I have a small electromagnet which moves a lever (it's a part from a larger device). I'm not sure of the supply voltage but other parts of the device required 20V. The resistance of the electromagnet ...
1
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1answer
104 views

Identification of 5 band Resistor from power supply

This Resistor is not functioning The 4th band is Gold, I've read that means it's an exception. The 3rd looks to me as silver, not gray, this is why I've added a picture. I'd like to replace it, so ...
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5answers
368 views

I don't understand why do I need to put a resistor between the gate and the source of a N-type transistor in this circuit

I have a diagram that represents a circuit whose purpose is enabling/disabling two leds basing on a logic programmed in a micro-controller. In the circuit below, as far as I understand, there are two ...
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2answers
78 views

What resistor to choose for circuit? [duplicate]

I'm not good at physics, but I'm trying to make a lantern. So I have an LED with this characteristics: N = 3 Watt I = 0.7 Ampere U = 3.4-3.6 Volt So I connect it to 6V battery, but need ~3.5 V. ...
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0answers
52 views

What resistor for uneven amount of LEDs in series, in parallel

I have an IR LED array which is powered by 12VDC. There are 10 chains wired in parallel. Each chain has 9 IR LEDs wired in series with a 10ohm 1/4 watt resistor. I also have 2 more chains wired in ...
5
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1answer
74 views

Please help with resistor color code?

I have trouble with finding out resistance of a resistor. It has 5 bands but somehow I cant get the code right.