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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Thevenized Resistance
Would anyone be able to guide me in setting up this thevenized circuit? I have researched/viewed a variety of videos/lectures and i cannot wrap my brain around this theory. I would greatly appreciate ...
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Is there a variable electronic resistor with a voltage less than 5 volts? [closed]
I'm trying to make my very small solar air freshener more light sensitive as well and I run on a lower amount of sunlight.
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12 volt resistance sensor to 5 volt
My truck has a 12 volt fuel level sensor that works based on resistance. Full the resistance is 33.5 ohms, empty it is 240 ohms. I'd like to take that signal and step it down to 5 volts for use with ...
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Measuring resistance of conductive carbon parts
I'm trying to set up a resistance measurement of a carbon infused pad. From specification I know the resistance should be around 500 Ohm, however, when pressed against two conductive surfaces using a ...
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Is a secondary resistance of 1.2 ohm OK in an inverter?
I have a Tripplite 750 A 12 V to 220 V inverter.
When I plug it in, the breaker trips.
I measured the secondary resistance for 220 V at 1.3 ohm. Is that normal?
The primary resistance for 12 V is 0 ...
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Limiting power in a circuit efficiently?
If you have an AC circuit and need to reduce the power going to your load, what is the difference between commonly-known ways of achieving that?
Because most of my electrical experience is related to ...
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Do the controlling voltages or currents act independent of the existence of a dependent source?
Dependent sources confuse me. We were taught a method using input and output resistances to find out whether a dependent source is VVVS, VVCS, CCVS, CCCS. Apparently for a voltage controlled source if ...
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What is the resistance seen by the three parasitic capacitances of the transistor
I'm looking for a general expression for the resistance seen by the three main parasitic capacitances of the transistor (Cπ, Cμ, Co) can anyone recommended me a reference book that have the full ...
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Equivalent Thevenin resistance
Do you know any applications that can solve the Thevenin resistance of this circuit?
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How can I reduce the parasitic inductance of a metal film resistance
One example of a common resistor is metal film resistor, which has a high ESL. What are the practical steps to reduce ESL, other than to increase the area of the conductor and reducing the length of ...
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Problem 2.13 from Hayt "Engineering Circuit Analysis" 8th edition
Here is practice problem 2.13 (p27) from Hayt's "Engineering Circuit Analysis" 8th edition.
"A 500 ft long 24 AWG soft copper wire is carrying a current of 100mA. What is the voltage ...
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Calculating Thevenin's resistance in circuits with a Dependent Source
Why can't I just add 1A current source through terminals a to b in this circuit to calculate the Thevenin's resistance.
I tried doing this using Norton's approach of short circuiting and it gave the ...
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Common mode choke DC resistance measurement technique
I am trying to measure common mode choke DC resistance to find out conduction loss due to DC current. I am using this (product link) one in particular. I measured the resistance between pin 3 and pin ...
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When current is passed through a wire, does it heat up uniformly, or is there a temperature differential?
When a current is passed through a wire (or a very long resistor), does the wire heat up uniformly? Or does it get hottest at one end and then get hotter down its length, following the flow of the ...
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How to find the current flowing through 2 different resistances?
what method do i need to find the current flowing in R1 and R5? and can you show me how, i still have difficulty in calculating the electric current in a complicated circuit
simulate this circuit &...
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How to determine the amount of electric current in the resistor R3
simulate this circuit – Schematic created using CircuitLab
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Transistor resistance
Isn't the general expression for the resistance looking into the emitter
$$Re=\left(\frac{Rb}{1+β}+Rm\right)||\,(Ro+Rc)$$
So when the base is grounded with \$Rb\$ connected, we see:
$$Rm+\frac{Rb}{β+1}...
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Generator With Adjustable Resistance
I'm currently working on a project that uses a DC brushed motor (24V, 350W) as a generator. I want to be able to adjust the resistance of the generator. The device will be battery powered, so ideally ...
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If more collisions happen with more resistance, why less heat is generated?
I was told the following. Given a wire with a battery connected to a resistor, the current is limited because of the resistance. This resistance is caused by subatomic interactions of the electrons ...
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Op Amp Feedback Resistors
When selecting feedback resistor values in operational amplifiers, how do you optimize the magnitude of the resistors? For example, I calculate the resistor 9/5 ratio value for a gain of 1.8
I know 5 ...
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Resistance vs Capacity in Building a Power Bank
I am building a power bank consisting of "12" 18650 cells arranged as 3 set of 4 in parallel and then putting the 3 sets in series to achieve 12.6 V more or less.
My questions are:
do I ...
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Need Help- Burglar Alarm System
I am making a burglar alarm system for my high school project. It uses a PIR sensor, a piezo buzzer, switch, battery, transistor, resistor and an LED. However, I have a 9V battery and a MPS2 222 AAAA ...
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How to find Rth for the given circuit?
I know how to proceed with the question after Rth is found but I am not able to calculate equivalent resistance for the given circuit. I am not able to resolve the 3 ohm and 4 ohm resistance.
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Resistance between any two points
I saw a series of simular questions, where was calculated the equivalent resistance of a circuit, but I don't understand a algorithm of calculation for a pair of specific points. I found a solution ...
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Resistance type and value [closed]
Resistance type and value please if any body identify
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Simple circuit analysis question, voltage across an unknown component
Question: Joe was debugging part of an experimental apparatus, probing around with his voltmeter. Part of the apparatus had two
obvious resistors in series with an unknown element, as shown in the
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How to figure out the optimal LED current for an optocoupler
I have a optocoupler PS817 that I plan to use for a zero-crossing detection circuit for mains 230 V AC.
But I do not know how to size the resistance of R1 and R2 mainly because: I do not know what is ...
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Is the coulomb unit a constant or does it depend on the wire?
I'm completely new to electronics, and I'm a bit lost on the definition of a coulomb. I tried to find a decent definition, but they all seem to equate to something like:
The coulomb (symbol: C) is ...
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Alternating current complex resistance
I am preparing for an exam and I am stuck on this task and cannot get any further. I would be very grateful for tips and advice. Thank you in advance.
Here is the task:
Two real coils connected in ...
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Resistances to two batteries where the bat1_pos + bat1_neg = bat2_pos + bat2_neg? But, bat1_pos is shorter than bat2_pos
SOK makes a unit called "12-Slot Outdoor Insulated Battery Rack – Fits SOK & EG4 Batteries"
In this configuration there are two batteries next to each other stacked six sets deep. Both ...
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How to design digital rheostat that can handle 100 mA?
Specification:
Bidirectional current
Output current: 1 uA to 100 mA
Terminals common-mode voltage: +/- 12V
That would be 24 Meg to 240 Ohm if that is possible.
Stability: +/- 1% if possible
Bandwidth:...
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Why do I have to increase the current by 2V when I am using a transistor?
I have a 3V 3W LED, which I would like to control with an ESP32.
For controlling the LED, I have chosen a TP122 transistor.
Here is my 'schematic':
The Arduino is an ESP in real life, and the 3 V ...
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How do I create a circuit to reliably calculate a range of unknown resistances?
I'm designing a low power circuit which serves to determine the unknown resistance across a 16 channel sensor. So far the results are bit subpar. The resistances are a function of a different applied ...
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Testing to find polarity of PCB power connector
I've got a PCB I ordered from China. It required a 5V input voltage through a barrel jack. The issue is there is no sign showing the polarity (positive or negative center) so I don't want to connect ...
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Why is there a sudden drop at the rest initial point after discharging? (trying to find IR Drop of LIC)
I'm trying to get IR drop of one of my LIC cells.
After discharge, at the initial point of rest, I believe there should be a sudden increase in the voltage due to resistance.
Does anybody know why is ...
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How to find current for Thevenin equivalent circuit
I'm trying to figure out how to calculate the Thevenin equivalent circuit for a voltage divider like the following one:
I understand that V_th is obtained by opening the terminals of the output, so ...
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Soft-start circuit for highly resistive load - negating initial voltage spike
I am trying to design a soft-start circuit for one of my projects which has a relatively large resistive load (~1MOhm). I found the following example circuit from an answer for a previous post (12 V ...
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LCR meter U1733C - R range mesurement
I have the LCR meter "U1733C" and I am little confused about the "R" scale. As I understand (the manual doesn't say it clear - maybe it is self-evident and I am missing something) ...
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Resistance Vs Reactance Definition
I am trying to understand the practical distinction between resistance and reactance. As I understand from all what I read the resistance is responsible for the current flow and the reactance is ...
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Find equivalent resistance of a resistor circuit [closed]
what is the process for finding the equivalent resistance of the following circuit?
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Why does a line-tester glow more when I touch the steel door frame?
I reassembled my line tester, and it was then that I got to know how it actually works. I know that when someone touches the metal part at the top, the neon LED inside glows. However, I have seen that ...
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Trying to understand (and mimic) the multimeter's interference with a circuit
I am trying to use a microcontroller to regulate the speed control of a sewing machine, rather than the foot pedal that normally serves this purpose. The pedal cord has 2 wires that connect it to the ...
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Find R value from capcitor discharge plot obtained using scope
I'm using an oscilloscope with probes that are specified to have to have an input resistance of 10Mohms, I apply 5 volts (using power supply) in parallel to my capacitor and use the scope in parallel ...
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Total Resistance
How can I calculate the total resistance in each circuit, assuming that every resistor has the same resistance?
Are the diagonal resistors in parallel?
I do not have any idea, so every kind of help ...
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Adjusting underfloor heating thermistor resistance to match a different controller
I have DeviMat underfloor heating installed in my bathroom, presently matched to a Danfoss DeviReg "smart" thermostat. There's a matching Devi heating probe installed under the floor which I ...
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MCAT resistor question
Example: Consider two resistors wired in parallel with R1 = 5Ω and R2 = 10Ω. If the voltage across them is 10 V, what is the current through each of the two resistors?
Solution: First, the current ...
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Why do I measure different resistances in the same wire at different current levels?
I've been doing some testing recently on the resistances of various pieces of aluminum for some applications. I've been measuring the resistances of these pieces by passing a constant current through ...
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How to find Thévenin voltage with dependent voltage source
I am not an electrical engineer, so I lack fundamentals. I was trying to solve for the Thévenin voltage, that is Vout at the open terminals A and B, but what makes it significantly difficult for me is ...
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calculating total current consumption before and after voltage regulator
I have a simple circuit.
IC1 is a standard 7805 voltage regulator.
Let's assume the battery G1 is 10 volts and all LED's each have 1V for its voltage drop.
Do I calculate total current consumption as ...
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