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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Why don’t external boards need a resistor?

I’ve been trying to learn how to use my MPU6050 chip. According to all of the tutorials/diagrams I’ve seen (one pictured below,) I don’t need to put a resistor in front of the MPU6050. Why is that? ...
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Amplifying sinusoidal signals

How can you use Proteus to design and simulate a circuit for amplifying a sinusoidal signal with an amplitude of 2V? Using Arduino uno and op amp
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1 answer
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12 VDC to 6 VDC to power a radio [duplicate]

I have a Grundig radio that requires 6 V and 500 mA negative center pin. It is very sensitive to noisy wall warts, so I want to power it from my very noise-free ham radio 12 V power supply. Can I use ...
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2 votes
2 answers
314 views

LEDs lowering my voltage

I'm getting to electronics and I have ran into a big issue. When I connect LEDS to my breadboard in parallel my voltage drops. I read in the past about series decreasing voltage and parallel ...
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2 answers
228 views

Question about capacitor and resistor in "power on reset circuit"

What I am reading has this circuit: It also has this description: In analog power on reset implementation, the time and voltage threshold factors are characteristic of an analog circuit. The time ...
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-1 votes
3 answers
83 views

What would be the loop equation for circuit including resistor, diode, light emitting diode?

I am new to electronics. What would be the loop equation for the following circuit? How would I find the current through the LED and the silicon diode in the circuit? Any help would be appreciated.
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1 vote
2 answers
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Analysis of circuit with dependent voltage source with no apparent solution

This is an exercise from Irwin's book, 9th edition. simulate this circuit – Schematic created using CircuitLab Although the book calls for the use of nodal analysis, I decided to do it by mesh ...
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2 votes
1 answer
44 views

Situation with controlled source in Mesh Analysis. Situations without solution?

I was analyzing the circuit below, and by using Mesh Analysis (this I am currently practicing), I obtained that the voltage at the \$6k\Omega\$ resistor (R6) is \$9V\$. I was able to work this out and ...
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Will a resistor used for an indicator LED in latching pushbutton negatively impact APA102 LED performance in same circuit?

Just to give a little more context to the picture below, I currently have designed a PCB that I will solder/reflow with APA102 2020 LEDs which will work in conjunction with mechanical switches also on ...
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15 votes
2 answers
6k views

Why is a 220 Ω resistor for this LED suggested if Ohm's law seems to say much less is required?

I am a beginner in electronics, so have mercy on me lol. I have been interested in this particular switch with a built in LED here https://www.adafruit.com/product/1476. According to the website, the ...
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High-voltage resistors versus anti-surge resistors

I am making a voltage divider with four 1M 1206 thick-film resistors and a single 2.7k resistor. The input to this voltage divider will be mains line and neutral. I want to measure the voltage at line ...
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2 votes
4 answers
435 views

Any difference in parallel and row resistor circuit?

My goal is to create a 1.5 ohm resistor. I have 2 ohm and 1 ohm ones on hand. My idea was either to create two 3 ohm resistors to connect them in parallel or connect them in row. See picture below for ...
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1 answer
81 views

Dual potentiometer the solution?

I'm working on retrofitting '14 Lincoln MKS 14 way power heated/cooled seats into a 2002 4Runner. I have all motors & lumbar wired. Had a Eureka moment on the TED and got it working! 3 position on/...
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Implementation of a 24 hour variable resistive load fluctuation

I am implementing a DC microgrid with a variable resistive load variation of 24-hours, based on a load profile. I have implemented it in MATLAB through a variable resistor and a 1-D block to provide ...
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3 votes
3 answers
112 views

General statement about arbitrary two-port resistor networks

Suppose I have a resistor mesh that is acting as a two-port network. I'm feeding in \$V_\text{IN}(t)\$ and I'm reading out \$V_\text{OUT}(t)\$. Here's an example of a potential circuit: Is it true ...
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2 votes
0 answers
54 views

How to choose component values for a JFET common-source amplifier?

I am trying to design a simple common source jfet amplifier using a J109 transistor. I'm using the J109 datasheet and equations from the book Electronic Devices by Thomas L. Floyd. The issue is that I ...
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10 votes
5 answers
2k views

What's the use of the 100 kΩ resistors in this schematic?

I saw a schematic for measuring AC voltage on a 3-phase mains supply (R/Y/B are the 3 phases and N is the neutral) I understand that the 1 MΩ and 2.7 kΩ resistors are for stepping down the voltage (...
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1 answer
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Equivalent resistance in simple Current Circuit

I have the following circuit (below). In order to calculate the current I1 as a function of the resistors and the voltage of the circuit, I'm doing the following: $$...
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1 answer
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First-order RC circuit

I have a first-order RC circuit without source and capacitors initially charged to +5 V and -4 V as shown in the figure. Initially charge sharing takes place between capacitors and v(a) = v(b) = 0.5 V....
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2 answers
56 views

CAN Bus termination resistor in only 2 device connection

A termination resistor in CAN ( .. or other differential pair communication like RS485 ) is necessary to absorb reflection. The value is related to wire length, electrical frequency, baud rate. It ...
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3 votes
2 answers
453 views

Order of an RC circuit

The circuit contains two independent state variables but the output of the circuit simulated in LT spice shows a first-order response. Where am I wrong?
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3 votes
1 answer
47 views

Resistor Power Rating and Pulses

I'm really confused with resistor power rating and pulses. I'm trying to determine the power rating of a resistor that will receive pulses of potentially 40 volts for 15 milliseconds. During this ...
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1 vote
4 answers
92 views

Understanding pull-up/down resistors for a GPIO pin

I'm a total beginner, trying to find my way through basic electronics... I went over some written material and YouTube courses, but there is something I don't think I get right. Consider my case - I ...
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0 votes
1 answer
125 views

Why does voltage decrease as resistor increases?

As you can see in the images below, when I increase the resistor value from 200 Ω to 2 kΩ, the voltage at the node Vd suddenly decreases. Why is this so?
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1 vote
2 answers
94 views

Changing LED from blue to yellow (car ambient lighting) - what is the purpose of the resistors?

I've got what looks like a fairly simple circuit I've pulled from a car door card. It provides variable brightness ambient lighting in blue, which I want to change to yellow for aesthetic reasons. I'm ...
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1 vote
2 answers
127 views

Three LEDs on consecutively with different time intervals

The title is referring to a youtube video if a 555 and CD4017 led larson scanner but this circuit only allows the LED to be on at the same time interval. Is there a circuit which can help to activate ...
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3 answers
72 views

Series/Parallel Resistor Association

My question is very direct. I understand the definitions and formulas involved in the association of resistors in both series and parallel, but when solving the circuit below, I don't quite understand ...
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1 answer
78 views

What value resistor is this? [duplicate]

I'd like to change this resistor from a main board but I'm not sure about its value. It's marked as 0.2R in the datasheet (so 0.2 Ω) but following the color code it should be 22.88 Ω. Am I right or I'...
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0 votes
2 answers
76 views

Phantom power voltage source high resistor [closed]

In PCB design I every time feel fear in my power trace included high impedance section or not? I've shocked on about 6k resistance putted on +48v of phantom power. I've heard this large resistor is ...
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-3 votes
2 answers
80 views

What value of resistor is needed to limit current to 0.5 ampere in a 12V DC circuit?

I have a 12V DC motor that uses 1 ampere from a 12V battery. I want to limit it to 0.5 ampere because it runs too fast on 1 ampere. I know that I can achieve that by adding a resistor but the question ...
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2 votes
1 answer
85 views

How to attach cable to a solder eyelet? [duplicate]

I believe that's what such connector is called. I want to attach 18 awg wire to it. Is slide on terminal the best choice?
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2 answers
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How to make two different frequency square waves stay in sync with each other at all times? [closed]

Is there circuit to make two square waveforms of different frequency be in sync with each other at all times as shown and not drift over time?
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1 answer
53 views

LED driver resistors

I'm designing a circuit using an LED driver that is intended for RGB LEDs and uses a resistor to set the current for the constant current supply. On the LED datasheet, each color is tested at ...
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39 views

Is this resistor manufactured by Piher?

I am attempting to determine if this resistor was made by Piher or not. The red color and glossy finish makes me think it was, however almost all the other Piher resistors I have seen have a different ...
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0 answers
53 views

Is this resistor metal film or carbon film?

I am trying to determine if this resistor is metal or carbon film? Traditionally most of the metal film resistors I've seen have been blue, while most of the carbon film I've seen have been light ...
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0 votes
1 answer
52 views

Use wirewound resistor as load

I want to use an array of ceramic wirewound resistor in series and parallel as the load of an 80W boost converter with the output of 400volts dc. Is it suitable to use 8 numbers of 10W resistors as ...
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3 answers
195 views

What circuit for the following input and output?

What circuit can I use to generate the following waveform, preferably using discrete components like transistors and resistors, but not ICs?
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1 answer
40 views

Question on Resistor and Capacitor Arrangement & Power Supply

I'm using this PHY My questions: Is it OK, if I connect 1uF and 1000pF capacitor on the VDDCR pin instead of the recommendation of "1uF & 470pF"? Higher capacitance on the power rail ...
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1 vote
1 answer
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What does a star symbol under a resistor indicate?

What does the star under the resistors R16, R17 and R18 indicate?
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1 vote
1 answer
35 views

Determine the min/max resistance of an SMD variable resistor

I want to determine my minimum and maximum resistance rating for my variable resistor but failed to find the relevant information in the datasheet (this might be an issue more 'noobs' might have, ...
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4 answers
109 views

Can I run resistor at a power higher than rated if I have external cooling?

Say I have a 1 ohm 100 W resistor that can work properly in still air. I now want to run it at 150 W, but I am also using a strong fan to cool it down to its usual temperature. Is this okay?
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1 vote
1 answer
100 views

How to avoid square wave parasitic oscillation?

I try to recreate the circuit from here using discrete components logic gates. How can I avoid these parasitic oscillations in a square wave in one of its outputs?
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-1 votes
1 answer
70 views

What is a safe amount of resistance required for a 9V battery?

I am new to electrical circuits and created the following circuit using falstad: With a 9V battery, what is the least resistance (instead of the 220k resistor) required to: Complete the circuit Not ...
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2 votes
1 answer
129 views

Pull up and down resistors at the same time

I have an I2C circuit with a 4.7 kohm pull-up resistor for each line. I think it might be a too strong (too small in value) resistor and the data isn't read properly. The processor I'm using has the ...
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1 vote
2 answers
69 views

Do I need a resistor for my doorbell wiring?

I bought a video doorbell that runs on battery and "trickle-charges" from the doorbell chime's wiring. But my street is so busy that the battery died in under a day. The support forum for ...
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0 votes
1 answer
38 views

Inductor and Capacitor 3-digit exponent value codes: is there a standard?

I've seen the standard NNX exponential value code where NN are the significant digits and X ...
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3 answers
43 views

Current limiter for VOD3120AB

I want to supply VOD3120AB with a voltage of 24v/2A from Power Supply. What is the value of the Resistor that I must add to the VCC of the VOD3120AB so that the VOD3120AB works properly? Information ...
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1 vote
1 answer
33 views

How to select current sense resistors for ir2136 ITRIP signal

Looking at the datasheet of the IR2136 it suggests this little resistor network as input for the ITRIP pin. https://www.infineon.com/dgdl/Infineon-IR213-DS-v01_00-EN.pdf?fileId=...
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2 votes
1 answer
61 views

How is MOSFET gate resistor chosen?

I have been doing research on MOSFETS. I see that in a typical circuit that includes a MOSFET and a Driver IC, there is a gate resistor. I have done research on this gate resistor and I am aware that ...
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1 vote
1 answer
54 views

12V on 24V PSU with Buck and Resistor

I have a 0.08A 12V fan that I'd like to run on a 24V PSU. I have a 1/4W resistor kit with several different resistor values and a max input 23V buck converter. Can I add a resistor in series before ...
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