It's a measure of how much an 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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48 views

1Mhz+ AC resistance measurements

Is a four point probe applicable for resistance/impedance measurements at high frequencies? Is there a more common technique for AC resistance/impedance measurements? Background: I'm coating ...
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2answers
70 views

what is the Outer casing of alkaline battery made of?

what is the outer casing of a typical small 9v alkaline battery made of? Is it conductive?
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1answer
25 views

compressor wiring resistance [on hold]

Hi I have a standalone freezer that stopped working. It has a single phase compressor. I read that the resistances between three terminals should add up, i.e. R1 + R2 ~= R3. However, my compressor ...
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1answer
45 views

Resistance and Inductance of a ceiling fan motor needed to spec snubber

I'm looking to specify (well, suggest) a RC snubber network for someone over on diy.se who is having EMI problems with his ceiling fan knocking out his TV briefly on turn-off: ...
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3answers
78 views

Obtaining a specific resistance

first of all, let me apologise for my inexperience with electronics. Now that's over with, I'm trying to follow a guide that specifies the use of a specific temperature sensor with an output of 5v ...
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2answers
71 views

How to find Equivalent resistance of solid regular bodies i-e solid sphere ,solid cube

How we can find the equivalent resistance of solid regular shaped bodies e.g solid sphere, solid cube
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2answers
85 views

Can a digital multimeter damage a powered circuit when measuring resistance?

I wanted to make sure my ESD wrist-strap is in working order. So I tested like this: Connected the wrist-strap to household ground (via wall socket). Measured the resistance between the wrist-strap ...
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2answers
65 views

PT100 calibration

If I take (say) a class B PT100 sensor with a stated absolute accuracy of +/- 0.3 deg and calibrate it with a freezing/boiling chemical at (say) 50 deg will that make it inherently more accurate when ...
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5answers
113 views

How do voltage, resistance and amperage work? (In DC circuits)

I have a (probably newb) question that I can't figure out. What I think I know is this: Voltage is electric potential (or rather a difference thereof) Amperage is the rate at which electrons move ...
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3answers
316 views

Next level of resistor divider

I know how to calculate proportions of resistor values in resistor divider, but dont know how to jump into "next level" and calculate the precise values of resistors from proportion : For example to ...
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1answer
41 views

What ppm/K correspondes to?

I have precision resistor 10 ohm and 5ppm/K. Does it mean that on delta 1K it will jump up/down 5 ppm of 1 ohm or 5ppm of resistor value - 10 ohms? I think that it corresponds to resistor value. But ...
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2answers
54 views

Crude simulation of a dc motor

I have a 24V battery bank and would like to discharge it in order to test the performance of different solar charge controllers. Eventually the batteries will supply a 2hp (1500W) DC motor and it is ...
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4answers
78 views

Why the output decreases in series?

I am just confused with below statement "A 100 W bulb is connected in series with a room heater. If now 100 W bulb is replaced by a 40 w bulb, the heater output will decrease !" if I follow this ...
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2answers
80 views

Formula for heat wire Kanthal or NiCr Watt consume?

The input voltage is 220v in single phase. How many watt consumed for Kanthal A1 (heat wire) AWG18 for 30m at 1400 degree Celcius ? How many If I use NiCr 60 or 80 with AWG18 ? Does anybody know the ...
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1answer
61 views

Determine connections of a transformer based on resistance

I have a small transformer I desoldered from a disposable camera that transformed 1.5V to high voltage >90V. It has three leads on one side and two on the other. I have been testing its resistance and ...
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3answers
72 views

Maximum resistance allowing for short circuits

Consider a contrived circuit consisting of only cell and pot: (1) a cell with constant voltage V and constant amperage A, (2) variable resistor of resistance R initially set to its highest finite ...
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2answers
72 views

How to measure the current drawn by the radio and the headlights from car battery easily?

I wonder how much current is drawn from car battery when the headlights and the radio are fully open. Is there a way to measure the resistance of the radio or the headlights without unscrewing or ...
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2answers
69 views

A Question on Resistance

A 19 v dc supply is switched to an IC amplifier. A 12 V dc, 100mA pilot lamp,(nonLED)is wired in parallel with the switch to indicate an active circuit. What size resistor is needed to support the ...
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4answers
67 views

voltage and current after closing the switch

In this circuit, the switch has been open for a long time that is the 2F capacitance is full. Now we close the switch. what is the equation of the current and voltage of the 2F capacitance after ...
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3answers
93 views

Why do only thick wires have less resistance?

I have learned that the thicker a wire is, the less resistance it has. However, this is not the case for other things such as a wall. If a (non-metal) wall is thicker it does not have a lower ...
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2answers
135 views

1000 watts, 220 volt, 52" length, Coiled Nichrome wire

I need to use Nichrome wire for heating purposes. My heating temperature could be among 200 Celsius, voltage should be 220V, wattage should be approximately 1000 Watts, and length should be 52 inches ...
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3answers
108 views

How does adding two Resistors in Series contribute to the sum of its resistances

I would like to know why by adding two resistors in series we would get a sum of it's resistances.I know by Ohm's Law that since $$R=\frac {V}{I}$$ it's certain that you would attain the equation ...
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3answers
77 views

Why resistance should be increased for Photoresistor in night for Street Lamps?

I can't get why the resistance for a Photoresistor should be increased at night time as said in Photoresistors. The reason is that I think that to turn on a light it's better not to have a higher ...
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1answer
43 views

Series Damping Resistor for Low-Speed USB

The USB 1.1 spec gives well-defined \$V/I\$ characteristics for full-speed output drivers, which can be used to find the series damping resistance, \$R_S\$. The low-speed output schematics also ...
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1answer
71 views

Input/output pin resistance for an AVR microcontroller

For example, when driving a logic-level MOSFET directly from a microcontroller, what is the smallest gate resistor that can be used? Specifically for AVR microcontrollers; i.e. this datasheet, the ...
4
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1answer
159 views

Maximizing force of magnetic mass accelerator

I am planning to build a coil gun to fire small neodymium magnets out of a pipe. For this I am planning to use a large 400 Farad 2.7 Volt capacitor. I am wondering how many coils of wire I should ...
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4answers
361 views

Why is resistance increasing while I'm measuring using a multimeter?

I have two copper strips with a one-megaohm resistor between them. That makes the resistance between the two strips 1 M ohm. I am measuring resistance between two copper strips using a multimeter. ...
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2answers
102 views

Regarding the design of a basic voltage divider

I've just entered the fabulous world of circuitry and was wondering about the design of voltage dividers. I understand their function and formula quit well, but was wondering about the actual ...
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0answers
40 views

Calculate a resistance - help with the signs

I have a problem with \$R_i\$, isn't it \$-\frac{v_i}{i}\$? My book report it in the solution as \$\frac{v_i}{i}\$ . Why? I know the question may seem trivial, but I'm a newbie to this field, so I'd ...
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3answers
358 views

Total resistance with resistors bridging two branches

I know how to calculate resistance in parallel and series connected resistors, and how to reduce most circuits to these, but I missed my lecture on cases where you can't just reduce the circuit to ...
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0answers
53 views

MOSFET impedance scaling

Suppose I have two devices. Both devices have the same gate length \$L\$ but device A has a much smaller width \$W\$. Device A has \$R_{\text{on}} = 1K\$ and \$R_{\text{off}} = 100G\$. Device B has ...
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1answer
48 views

Inverting effect of resistance in an RC circuit

I have a question on basic electronics. I'm looking at a very simple CMOS RC Circuit around a Schmitt Inverter which creates square waves. Something like this. simulate this circuit – ...
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1answer
68 views

Whether Internal source resistance will have effect on the circuit

Calculate the voltage gain for the network of Fig. 3.12 if the source has an internal resistance of 100 in series with Vi.Vi=500mV,R= 1K ? For this problem I had tried a solution but I am not ...
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1answer
103 views

resistance measurement problem with digital multimeter

I accidentally caused a short circuit with DMM common lead while measuring 220 AC voltage. then when I tried to measure resistance it gives me a reading of 3500 ohm while there is no resistor ...
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2answers
135 views

Voltage Division Problem

Hello good EE samaritans, I currently taking MIT 6.002 course to get head start prior to starting EE next Fall. Right now, I am really struggling with this first lab. Problem: You have a 6-volt ...
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5answers
113 views

Circuit Simplification

Calculate the current shown by the ammeter. simulate this circuit – Schematic created using CircuitLab How do we solve this using delta-wye transformations?
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1answer
87 views

Charge pump output resistance

I am designing (simulating in LTSpice and building on a breadboard) a charge pump to power my numitron tube. I need to get ~15-20 V out of 3.3 V. The circuit is as follows: simulate this ...
2
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2answers
105 views

How do we predict if power loss will increase or decrease in a DC circuit?

I want to know whether it is possible to predict if power loss will increase or decrease in a circuit with a fixed EMF, a fixed resistor in series and a variable resistor in series. If we change the ...
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2answers
161 views

Current capacity of wires

So this question stems from a previous question. Here Where from several tables one can see that the maximum current (Imax) is proportional to \$1/R\$ where \$R\$ is the resistance. (Or that ...
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1answer
44 views

Resistance and voltage drop conclusion [closed]

Is it true that the higher the resistance the higher voltage would drop?
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1answer
111 views

How do I find the equivalent resistance using symmetry?

I know this could be solved using delta-to-y transformation, but I want to solve this using symmetry. Considering the middle line the symmetry axis this becomes: simulate this circuit ...
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6answers
179 views

Is there a non recursive formula for mixed resistors?

In equivalent resistors in multiple parallel resistors, like this simulate this circuit – Schematic created using CircuitLab I need a formula for the equivalent resistance for the ...
2
votes
2answers
135 views

How much current does a typical multimeter draw to measure resistance?

Assuming it's running on a 9V battery like most multimeters are, and the setting is on MegaOhms. How much current will be drawn from the internal battery?
-5
votes
1answer
83 views

110v 220v do it work? [closed]

i bought hookah heater from amazon. this product link is ...
1
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1answer
52 views

definition of input/output resistance of a circuit

Is input resistance always a small signal parameter or is also defined for large signal model of any circuit? How do we model any circuit after we calculate its input/output resistances?
30
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6answers
3k views

Using a bottle of water as a resistor

Today, while drinking some water from a \$500mL\$ bottle, I started reading the info about the water and found out that the conductivity (\$\sigma\$) at \$25°\$C is \$147.9\mu S/cm\$. So it came to my ...
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2answers
67 views

Real equivalent of terminal resistance

I found in a book a scheme representing a terminal connection used in making an ammeter shunt (with the purpose of extending its measuring domain). I can't understand what the drawing at b) ...
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2answers
63 views

Are all solenoids waterproof?

I have an application where I need a solenoid to control a valve at the bottom of a tank. For unimportant reasons the valve needs to be inside the tank at the bottom. I was wondering are all ...
1
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0answers
87 views

High resistance (100Mohm) control using constant voltage or current source

I want to control resistance (100Mohm) programmatically. I found on this site that photoFET can solve this issue by sourcing constant current. From my understanding FET can give resistance control ...
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2answers
154 views

Thevenin's equivalent of Wheatstone bridge

I tried to calculate the Vos and Isc and both of them are zero..so the Thevenin's resistance is 0/0=undefined. How do I calculate the resistance when Vos/Isc fails,such like the Wheatstone ...