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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38 views

e12-table - replace resistors

Is this the table of 12 resistor series? 10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82 http://sv.wikipedia.org/wiki/E12_%28resistorserie%29 And if I have a resistor of let say 1670 ohm - how do I ...
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2answers
112 views

Trouble converting 12VDC incandescent to LED: lack of resistance

I'm converting two, independent, incandescent bulbs (OEM 212-2) fixtures to use LEDs for automotive map reading. Each incandescent bulb (12-volt/system) measures 1.5 ohms with a meter; however, there ...
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1answer
64 views

Is there a way to find this resistance? [duplicate]

I have done thevenin analysis on a larger circuit and have gotten the result below. I need to find the value of RL. Would I use thevenin again? But that would give me the same result because I would ...
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2answers
74 views

Grounding a wire using a chunk of metal?

So I've made a complex LED grid and it works but has ghosting in some of the rows. I've given up trying to work out the reason why, but have noticed that when I touch the SCLK wire, or connect the ...
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1answer
59 views

Voltage used up by a transistor and shift registers

i am on a project 8x8x8 LED cube and I am stuck on the value of register i should use. Talking about single layer I am using 2N5296 transistor for common cathode and 8 shift registers for controlling ...
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0answers
34 views

fuse metal alloy with high springiness?

Is there a fuse alloy that would have the same springiness as this except with a little wire that comes out and that plugs into something, so that it could be machined and pressed from one single ...
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2answers
40 views

Potentiometer with No Minimum Resistance

I'm looking to create a variable current regulator with the LM317 using 1-turn pots. I know that I am going to need to have a resistance of 1.25 Ohms to have a current of 1A, which I want to be my ...
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1answer
20 views

Max Voltage of Electrical Stimulator for Cardiac Tissue Bioreactor

I'm designing a bioreactor that will electrically and mechanically stimulate cells in media in an incubator. I'm using monophasic, square waveforms and have a max stimulation level of 12V/cm, else ...
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1answer
47 views

How does switch interfacing work?

This is a basic question, but I don't have a background in electronics so I find it difficult to wrap my head around the concept of how current flows. I have chosen this simple example of interfacing ...
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1answer
52 views

Measure inductor coil's resistance using multimeter

simulate this circuit – Schematic created using CircuitLab Above is the set-up of my simple experiment to determine the inductance of an inductor. The voltage across resistor R (5 ohms) ...
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1answer
55 views

What determines the amount of power sent to a device?

I have various devices that draw amount different amounts of power from a micro power connector. If I have a 240V socket plugged into a device which draws 4W of power, does this mean that the power ...
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0answers
31 views

modeling AC resistance proximity and skin effect using LTSPICE

I'm designing an air-core loop receiving antenna from <1Hz - 50kHz. Is there a way to approximately model the skin/proximity effect using lumped circuit parameters in SPICE software? I think you ...
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2answers
244 views

How do I work out what resistor to use?

I am trying to work out what resistor to use in a circuit. The circuit is a series circuit. The power to the circuit is 5.5V, with a switch, which connects to a GPIO pin on the RasberryPi. I believe ...
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0answers
50 views

How does temperature affect the performance of an SMPS?

I have an SMPS (laptop AC adapter) rated for 180 W that is presently operating at capacity. The output seems to be limited by internal resistance, but I can't really tell. I'm trying to get it ...
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0answers
55 views

Mosfet small signal input resistance from source

Considering the T model of MOSFET for small signals I want to obtain the input resistance from source to gate. simulate this circuit – Schematic created using CircuitLab The current ...
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0answers
31 views

Is the armature resistance of a DC motor the sum of the resistance of each winding?

I am aware of a number of methods of measuring the armature resistance of a DC motor including locking the rotor, giving a fraction of the rated voltage, measuring the current and calculating the ...
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2answers
61 views

Output Voltage Swing vs. Load Resistance of an Op Amp

What does the "Output Voltage Swing vs. Load Resistance" signify? Lets say I want to get a gain of 400 from an op-amp. I can use any one of the following combination Gain = -(R2/R1) Case 1: R2 = 400 ...
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1answer
39 views

electret microphone dynamic impedence

how much is the dynamic impedance/resistance seen from a electret microphone? I am trying to design a microphone preamp and need to know seen resistance in small signal from the signal source ...
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4answers
254 views

Formula to find out the resistance per meter of a specific gauge of wire if I already know the resistance of a different gauge of wire per meter?

So if I know a 30 gauge wire's resistance at 1 meter, how can I figure out the resistance of a 29 gauge wire at 1 meter long of the same material? Or 5 gauge, or any other gauge? I need a formula, not ...
2
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1answer
176 views

Does the MOSFET Rds(on) value really matter?

I am using MOSFETs in the ubiquitous RAMPS 1.4 Arduino shield for 3D printing use. The MOSFETs switch the voltage to the heated bed and the hotend (where the filament comes out). I need to replace ...
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2answers
48 views

Finding input resistance for this circuit

How do I find the input resistance for this circuit. I think it should be infinite but not able to analyse properly. Thanks.
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2answers
89 views

Voltage vs current vs resistance - did I understand them right?

I'm currently getting started to learn about electrical engineering, and I'm having some difficulty separating voltage from current. I have seen a couple of times that a battery is compared to two ...
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1answer
88 views

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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1answer
83 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
136 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
90 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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1answer
77 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
80 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 ...
2
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4answers
98 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
69 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
111 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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1answer
66 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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3answers
67 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
79 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
116 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
52 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
122 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
91 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
91 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
134 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
114 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 ...
3
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5answers
178 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 ...
2
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3answers
325 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
121 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
94 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
90 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
409 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
72 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
88 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
98 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 ...