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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IRF540 power Mosfet 12 volt motor gate resistance

I have a IRF540 power Mosfet driving a 12 volt motor. Currently I am using a 100 ohm gate input resistor, It is working fine. What I want is the maximum gate resistor value that I can use and still ...
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73 views

How to create a simple circuit with your body

I recently visited a museum with my son, and we both enjoyed an exhibit where there was a partially completed circuit that was completed when you touched the two end points or joined hands and each ...
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5answers
131 views

The path of least resistance

i always knew that current will take all paths, even the other post on this forum said so, but i was doing this RC circuit today where the resistor and the capacitor are wired in parallel, i was told ...
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3answers
80 views

Calculating voltage in diode circiut

Could you explain to me why U_out is -4,4V and only 3rd diode is open in the following example? Given that R is 10kOhm. My physics resistant brain tell me that voltage at each anode is is 10,15 and ...
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50 views

What is the equivalent resistance in this part of the circuit?

I broke the circuit down into as basic as I can take it, and I know what X and Y are, but I can't figure out the equivalent resistance of the circuit in the middle. It seems to me like the current ...
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2answers
58 views

Resistance as a function of base voltage in a transistor

In this very interesting introductive video https://www.youtube.com/watch?v=CkX8SkTgB0g, I learned that a transistor is basically nothing more than a resistor whose value changes accordingly to what's ...
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4answers
80 views

Input and output resistance of an opamp circuit

Recently we have been working with opamps in the lab and I never can understand how to determin the output and input impedance of a circuit with op-amps (not the input and output inpedance of the ...
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1answer
63 views

Could cold Solder be the cause of burnt components?

I have a mainboard of a slot machine that has burnt resistors. I wonder if this could be related to cold solder, because the slot machine remains on for long periods of time (months at a time) and ...
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1answer
71 views

How to shift resistance range of Linear Potentiometers by X ohms in the Positive or Negative direction?

For example, I have a 10k ohm (linear) Thumbwheel Potentiometer. This POT will produce values from 0 to 10k when reading its resistance. Positive Shift How do I shift resistance range values by X ...
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41 views

circuits in electricity, find voltage [duplicate]

find potential of point D. i want to make it clear that its not my homework. i gave an exam and it was one of the questions i couldnt solve. i have already got my result for that exam . i am an 11th ...
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57 views

What resistance should I expect when testing capacitors?

I'm trying to troubleshoot why my TV isn't turning on and was advised that it might be an issue with a capacitor. There are no visible signs of bursting or leaking on any of them so I've started ...
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20 views

how to determine length of nichrome wire in respect to temperature [duplicate]

If anyone of you help me in finding specification(awg of nichrome wire required) for a 2 m nichrome wire to heat up to 65 degree Celsius .Voltage applied is 12 v.I want to use it by coiling it to ...
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65 views

A circuit to convert some resistance values to others

I'm looking to build a circuit to convert an old steering wheel remote to a newer head unit. Both work with resistances, but have different values each. So, what I would need to build is a circuit ...
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1answer
61 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
84 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
42 views

compressor wiring resistance [closed]

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
62 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
86 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
78 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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102 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
77 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
132 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
319 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
58 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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65 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
83 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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129 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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65 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
77 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
76 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
69 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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119 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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196 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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109 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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84 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
49 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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83 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 ...
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1answer
170 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
370 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
103 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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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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368 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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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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54 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
73 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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118 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
175 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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123 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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104 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 ...