Unanswered Questions
973 questions with no upvoted or accepted answers
4
votes
0
answers
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Electrical circuits homework
I am pretty new to circuits analysis and I have the following problem as homework:
ig2(t) = 4sin(ωt + π/4),
e3(t) = 12sin(ωt + π/4),
R1 = 10 Ω,
ωL1 = 4 Ω,
ωL3 = 3 Ω,
1/(ωC2) = 6 Ω
I have to calculate ...
- 84.8k
4
votes
1
answer
141
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Output voltage not stable - What is compensation with respect to DC-DC (buck converter)?
EDITS:
Input voltage range: 24V to 48V.
Changing the load current from 0.38A to 1.018A increases the mean output voltage from 12.779V to 13.26V. The supply should be producing 12.5V.
I'm using this ...
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3
votes
0
answers
109
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Problem with ESP32 and Wifi when powered by LiPo battery
I built a circuit around a ESP32 powered by a LiPo battery (I tested with 1800mAh and 4400mAh batteries), a MCP73871 to charge it and a TPRT9080 to regulate voltage.
When I use the ESP32 without Wifi, ...
- 31
3
votes
1
answer
80
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LDO voltage regulator malfunctioning as passthrough after 24/7 usage
I have designed a custom pcb utilizing the ENC28J60 ethernet chip to be used with raspberry pi. The board has 5V in which powers both the ENC28J60 (through a AMS1117-3.3 LDO regulator) and the pi. ...
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3
votes
0
answers
104
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How to interface buzzer with LED in this circuit
Below is the circuit where I want to integrate the buzzer with the red LED.
The task is to add the buzzer, where the red LED is, in such a way that when the red LED (which is driven by the LED driver)...
- 31
3
votes
0
answers
122
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Is it possible for one oscillator to drive two ICs?
I have this oscillator IC with which I plan to drive a KSZ8795 and an LAN9500A without clock buffer.
The TG2016 output load drive is 10pF for the capacitor.
The KSZ8795 can have a crystal load ...
- 72.5k
3
votes
0
answers
161
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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 ...
- 163
3
votes
0
answers
96
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How to indicate an android tablet is actively charging with LED?
I am a rank beginner, and I do feel like I am missing something pretty obvious here, as the problem doesn't seem that complex. (I know... famous last words)
Problem:
Android tablet (in a completely ...
Null♦
- 7,623
3
votes
0
answers
530
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LM339 LED voltage indicator behaving opposite of expected
I have built the attached circuit and am pretty confident it is correct with no short circuits. When it's powered up with a 9V battery, all 4 LEDs light up with no input voltage. As the input voltage ...
CommunityBot
- 1
3
votes
0
answers
75
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frequency of MCP3008
I built BOOST CONVERTER,
I sample the output voltage with A/D and control it
using RASPBERRY Pi3, I set the switching frequency of the BOOST CONVERTER 70KHz,
and the frequency of the MCP3008 1.35MHz,
...
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3
votes
0
answers
147
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Arduino Every Nano with 3.7V Li-Po - Reading voltage
I have Arduino Every Nano and 3.7V Li-Po battery (Akyga LP903759). I want to read the current voltage of a battery using analog pin. If I use a 50 kOhm and 200 kOhm resistor (in voltage divider) I'll ...
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3
votes
1
answer
534
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Where does the 1 V voltage come from?
I have a PLC with many digital open collector outputs connected similarly to the schematic below.
If I use a multimeter and measure the voltage between the two points in the schematic, it is showing 1 ...
CommunityBot
- 1
3
votes
0
answers
2k
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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
answer
437
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Activating a relay when certain voltage received (Water injection system)
I decided to build a simple water/methanol injection system for my car and now I'm thinking about a simple way to activate the water pump only from certain boost level. For the boost reading I'm ...
CommunityBot
- 1
3
votes
0
answers
2k
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PSpice VSIN frequency - how to set it in rad/s?
I know, that if I want to set FREQ, I need to set it in Hz, not in rad/s. I know, that
1 Hz = 2*pi rad/s,
but how to do this in PSpice? What should I enter exactly?
and btw. if I want to set VOFF (...
- 17.7k