Unanswered Questions
1,017 questions with no upvoted or accepted answers
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Electric grid power transformer winding: If it is milliohms, why does 9V DMM show infinite ohms?
When testing large MVA power transformers, like 66kV to 16kV, the winding resistance in DC ohms is milliohms.
It takes a high current supply to do this, then the V is measured across the winding to ...
CommunityBot
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4
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How to make your own EL Wire (electroluminescent wire) inverter
I would like to make an EL wire (electroluminescent wire) inverter because I can't seem to find a commercial inverter that can drive the right length of wire from the batteries I would like to use: ...
- 3,621
3
votes
1
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How do calculate power consumed by a BLDC motor using two-wattmeter method
From https://www.studyforfe.com/blog/steps-for-solving-the-two-method-wattmeter-problem/ :
$$\begin{aligned}
W_1 &= V_L \cdot I_L \cdot \cos(30°+\phi) \\
W_2 &= V_L \cdot I_L \cdot \cos(...
3
votes
0
answers
106
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Unequal resistive power splitter
I'm looking at a 3-port, unequal resistive power splitter design like the dashed-line box in the diagram.
1 is the source, whereas 2 and 3 are two loads of impedance, say Z0. All 1, 2, and 3 are ...
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3
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Is 1800A a realistic current for a mains wire?
(Moved this question from the Physics SE since it's apparently not suited there)
I recently encountered this elementary physics question:
A mains wire outside your house is 15m above the ground. The ...
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3
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434
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Is a single Schottky diode adequate to support power-path in a basic USB -> LiPo charging circuit?
I'm working on a hobby project based on the ATmega32U4. I'd like to be able to power the device by USB or LiPo battery. I was looking at the schematic for the LilyPad ProtoSnap Plus and saw a diode ...
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171
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Estimating beat frequency amplitude caused by non-synchronized downstream buck converters
I was reading a TI app note “Synchronizing DC/DC Converters in a Power Tree” which showed how subharmonics appear on the input voltage line when it powers two buck converters with different switching ...
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Supercapacitor spot welder - which capacitors to use?
I built a spot welder using a big transformer (approximately 4kW from an old welding machine) but I now need to build a spot welder with more power (more current.)
The current spot welder works great ...
- 72.5k
3
votes
1
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Acceptable designing two clock generators using single package?
The circuit I usually use is Pierce oscillator:
(pic source)
I have always had single system clock in the system, built on single HCU04 chip. Now I need two: 6*NTSC and 4*PAL - frequencies not ...
- 96.8k
3
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Power use question for a trail camera
I am trying to calculate how long that a trail camera can be deployed before the batteries run out. The trail camera in question is a Reconyx HyperFire 2.
Here is a useful review of the trail camera ...
- 175k
3
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1
answer
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powering a circuit with USB micro; what to do with unused pins
I want to power an old board (mostly TTL ICs) with this through-hole USB micro AB connector. I will have to create the pads for the pins with a scalpel, so the main question is: can I just connect the ...
CommunityBot
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2
votes
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Buck Converter Current Mode Control Simulation
I have downloaded LTspice PWM switch from christophe basso website http://powersimtof.com/Spice.htm file name PWM-CM2-MD2 by Mark Dimattina
I am doing 5.1V converter based on LTC3890 IC so I tried to ...
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99
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How does this input filter circuit work?
Looking through a schematic for an Analog Devices evaluation board, I got to the power input circuit but I couldn't make sense of it.
The full schematic can be viewed here
...
2
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187
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Problem with battery power circuit
I am a 14 years old boy and I am currently making a MacroPad with a 3.7V battery and a charging circuit but powering the circuit with a battery does not seem to work. I also have made some ...
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2
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1
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Two NiMH AA batteries powering servo circuit
My project has an ESP32 C3 and 9g servo. It has to be mobile, thus battery powered. Due to space constraints, I can’t use 4 AA batteries even though that would be ideal. I would like to use two NiMH ...
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