# Questions tagged [resistance]

A measure of how much a conductor opposes current flowing through it. It can also refer to a part of a circuit, which has a non-negligible resistance value.

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### Calculate sheet resistance in finite element method

I have a simulation with several polygonial mesh cells (Voronoi-mesh) and their centers of gravity $P_i$, each with its own electrical potential. Every cell has the same height $h$ all over. How ...
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### 120 Watts and 7.2 Volts, how many Amps?

For a project I need to switch on a simple handheld vacuum cleaner with an Arduino. I am thinking of using a relay or mosfet. I opened the case and a 7.4 V 2200 mAh Li-Ion battery powers the motor, ...
43 views

### Switching depending on resistance from fuel gauge sender unit [closed]

I hope someone can offer a solution to the following situation: We currently have a fuel gauge operating at between 12,6 and 14,6 VDC. The sender unit ranges from 10 ohms (empty) to 300 ohms (full). ...
37 views

### Effective impedance calculation for noise removal from supply

I am working on single supply Op-Amp amplifier, referring to this post. While calculating the value of the capacitor C2, as to pass all the noise from the supply to the ground. I am unable to ...
103 views

Admittance is the reciprocal of impedance. But: 1) Susceptance is the reciprocal of reactance, or the imaginary part of admittance ? 2) Conductance is the reciprocal of resistance, or the real part ...
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### Difference between using large vs small test resistance to check internal DMM/SCOPE resistance

For my intro lab to my Analog Electric Circuits class, one of the analysis questions is to calculate the internal resistances of the digital voltmeter and the oscilloscope, using the equation The ...
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### Ethernet Cable - How do I measure the capacitance, Inductance and resistance? [closed]

I am interested in knowing how to measure the Inductance, capacitance and resistance of Ethernet cable? From what I understand, Ethernet cable have resistance, inductance and capacitance. Is there a ...
35 views

### What component can I use to control the brightness of an LED strip?

I know that to adjust the brightness of a single LED, I can control the current using a resistor. What about for a strip of LEDs being fed by a 24V 1.8A power supply? I'd assume that the power being ...
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### Switched capacitor resistor

I have some basic doubts about switched capacitor resistors: With this circuit we get an equivalent resistance equal to (Reference: Wikipedia): Where f is the frequency of the clock signals that ...
169 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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### Amperage limiter?

I'm looking for a component that essentially limits the current passing through it, but unlike a resistor, its resistance is not constant. When the current passing through this component is below the ...
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### How a circuit get short [closed]

I am a high school student learning about the circuit, and how the current choose the path with low resistance, I have seen circuits and how one of the resistance among the other resistance get short....
58 views

### Increase resistance to turn on a light bulb

I’m wondering if it is possible to use a potentiometer to turn on/off a lightbulb in a binary manner. I’m thinking high resistance = light on. Low resistance = light off. Is there such a circuit? ...
134 views

### Thermal resistance - Temperature transistor

I have a transistor with Vsupply = 24VDC, VCEO = 45VDC, ICE = 20mA. How to calculate the delta T (rise in temperature) of this transistor. I would like to know what thermal resistance I may have at ...
26 views

### Trouble understanding thevenin's model from AoE Lab

I am using the AoE lab book to teach myself electronics. I am on the voltage divider section, and I am confused at their simplified explanation. I'd like to explain it a different way, but I am not ...
33 views

### What is the difference between transresistance and differential resistance?

Transresistance is defined as the change in output voltage over change in input current. While differential resistance is defined in the same manner. So what is the difference ?
294 views

### Microcontroller - Measure Resistance in Circuit

I am creating circuit that will control power of heater coil. For controling power I am using Arduino PWM that controls voltage and by Ohm's Law I am calculating desired power. P = V^2 / R Now the ...
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### Calculating resistance for integrated circuit with logical gates, so that the circuit works properly

I have found this task with its solution: For the circuit shown below calculate $R$ so that the circuit works properly. All gates belong to the $TTL$ series. Solution: \begin{...
49 views

### How to find equivalent resistence of this mixed circuit?

Find equivalent resistance, the current in R5, Voltage of R2 and power of R10. Actually, I don't know if my attempt is right. So, you would point out where there are mistakes, pleased. R10 and R11 ...
22k views

### What are the terminals in this 6 pin potentiometer?

I want to use my 6 pin potentiometer in circuits so I want to know what all the terminals are for. I know the basic principle in the 3 pin pot. I'm completely new so please answer it in simple terms. ...
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### Measuring Voltage drop across MOSFET 2N7000

My setup is 2.1V on the gate. A 330 Ohm load between Vdd and drain. And Source to ground. I stepped Vdd from 0V to 9V in small increments and measured the current through Vdd to ground. Got currents ...
71 views

### Fraction resistance and negative resistance

Is it possible that the resistance will be fraction or negative number and what's happened?
165 views

### Can a resistance be negative?

I have to calculate the value of a resistor so that my circuit has a certain equivalent resistance. This is the circuit, and here are the values: ...
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### Finding R equivalent

simulate this circuit – Schematic created using CircuitLab When finding Req between M and N i can't understand why current isn't flowing in R3 and R4.
250 views

### How to use a multimeter to test the resistance of my tongue?

I just purchased this cheap-o multimeter: https://www.amazon.com/AstroAI-Digital-Multimeter-Voltage-Tester/dp/B01ISAMUA6/ref=sr_1_1?keywords=astroai+am33d&qid=1551837071&s=gateway&sr=8-1 ...
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### Current and resistance

Can anybody explain why my tongue gets a reading on a multimeter. Do I have a current? Why do i have resistance? Why do some things have resistance? I am very confused.
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### How does an e-cigarette dry tank protection sensor work?

E-cigarettes work with a resistance coil which heats liquid into vapor. Some e-cigs have a dry-tank protection, which senses when the coil does not have any liquid to heat, to avoid it getting too hot....
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### Ground with one sensor vs multiple sensors

I'm pretty new to the world of electronics and was working on an Arduino project using load cells and HX711 amplifiers. The project consists of four HX711 connected to the Arduino and Pi, with all ...
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### Circuit solving problem

I am a high school boy and came across this question: I have solved this question by KVL, but how do I solve this question by potential distribution method? What I have tried :) I assume two ...
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### Finding Equivalent Resistance - does order matter?

Conceptual question: When you have a super complicated circuit, does it matter which node you start at when finding equivalent resistance? How about capacitance?
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### How to calculate equivalent resistance in this circuit?

What is the way to calculate the equivalent resistance between this two terminals? This is pretty simple circuit but i'm not sure what is ok to do and what isn't
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I've found a something quite odd with measuring the resistance of a 36uH inductive load (see this earlier question). I can measure the resistance, which is quite low, but then disconnect the probe and ...
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### Is power balance a relevant factor in the consumption of a house?

Where I live, houses receive up to three phases from the electricity provider. There is a company advertising a power balancing service. They claim that if one of the three phase cables is overloaded,...
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### Role of independent and dependent sources when calculating equivalent resistance

There are plenty of topics about this question, but I did not find a precise answer. Let's consider two points A and B of a generic circuit and suppose you want to find the equivalent resistance ...
21k views

### Increasing resistance on speakers

My amplifier is rated at 8ohms for my surround sound but my speakers are 6 ohms. The owners manual says that if the speaker resistance is too low the power protector will blow and that is exactly what ...
43 views

### Reading of megohm during ground check

During the check of pins on connector with a multi-meter, one of the pins that goes through the relay to provide ground signal, I am getting 8MOhm (8 megohm). I should not be getting anything on that ...
6k views

### Are these 2 resistors in parallel?

So I had a circuit to analyse and I needed to find the equivalent resistor and then I arrived to a confusion. Are R1 and R3 in parallel? Here is the circuit. simulate this circuit – Schematic ...
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### Thermal resistance of Thermal Interface Material

Can anyone please give information how to calculate the thermal resistance of SIL PAD "TSP A2000" from make Berguist. from The data sheet its specified thinness is 0.254mm, Thermal conductivity (W/m-...
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### Reducing the circuit

I am high school boy, our teacher gave us circuit and we have to find out the equivalent resistance. . Our professor gave us idea that we can solve this question either by either superposition ...
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### Need help to analysis & overcome an issue with LM358 OP-AMP

I want to measure the resistance of a coil which its resistance vary in accordance with its temperature coefficient of resistance, the resistance range of the coil vary between 0.12 Ω to 5.00 Ω, at ...
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I have one question with this topic: lm35 Temperature Readings are not right after sealing with Hot-melt adhesive (How mush has it Soldering max Temp toleration ?) it answered by this (Thanks from @...
243 views

### Can a Dependent source be dependent on itself?

I am looking for the Thevenin Resistance here. However, I have no clue what to do with $i_b$ and the source dependent on it. This is the entire circuit. $i_b$ is the current through the 5\\$k\...
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### Cable length and voltage drop in offgrid solar installation

I have connected my Lithium-ion battery pack(11.1v 100ah ) with my Epever MPPT charge controller using 5M length of 8 AWG cable. when i put load which consume around 12A , the charger controller shows ...
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### How do you calculate the noise of an op-amp circuit?

I think I know how to do this, but you can find a lot of different instructions and calculators online that contradict each other. I have yet to find a clear, concise procedure for calculating the ...
3k views

### What is the physical meaning of negative resistance?

I am a bit confused about the physical meaning of negative resistance. Mathematically, a component which has negative resistance shows a decreasing voltage across its terminal when the current inside ...
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### What's the equivalent resistance of this circuit?

I am a student in 10th grade and our teacher gave us this schematic to work with (Remade with circuit lab): simulate this circuit – Schematic created using CircuitLab He asked us to find the ...
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### Why for a dipole antenna half wave length is optimum size?

For a dipole antenna, half wave length is optimum size. Why is this so? What I understand is that radiation resistance of antenna is around 50 ohms at this size, which matches with the characteristic ...
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### Find armature resistance on DC shunt generator

A DC self excited shunt generator has a field resistance of 160ohms generated emf is 420v and supplies a load of 55kw how would u go about calculating armature resistance when terminal voltage is 408v ...