Questions tagged [current]

Flow of electric charge - typically movement of charge carriers, such as electrons. Measured in amperes (A).

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Is there a simple fix for summing 2 AC signals?

I have seen many mixer schematics. They are pretty much always the same - a stack of resistors. Even some DJ mixers using the SSM2164 simply joined outputs followed by an opamp. The same thing always ...
63 views

Finding Current Used by an LED

In the Arduino Start Kit, the first circuit is very basic: 5V power, 220 ohm resistor, and an LED with a forward voltage of 2.2V. However, here's two things I can't reconcile: The booklet says that ...
51 views

$\delta n \cdot x + n \cdot \delta x~$ equation of shrunk coil with incremented number of turns per unit length

The very long coil exists with the following information . $$a:=\text{radius of the circle of the coil}$$ $$n:=\text{number of turns of the coil per unit length}$$  x:=\text{lenght of the ...
58 views

Why is voltage subtracted in this 2-resistor circuit to find the current?

I am figuring out the current for the following circuit: Using V = IR, I would expect to do I = V / R and then do: I = (20 + 50)...
61 views

Calculate maximum allowed current of a cable with AWG, length, and voltage? [closed]

How can I estimate the maximum current of a cable with thickness, length, and the voltage? Assuming that the material is cheap aluminium, not expensive copper, and in room temperature. For example, ...
46 views

Why do pcb in battery reduce the input voltage that goes to the single cell li ion battery [closed]

And... Why do li ion battery cut when charged directly with 5v and 1amp
57 views

Inrush current and locked rotor current

The way I understand it is as follows: Inrush current is the high current drawn by a motor during its acceleration period. Inrush current begins when the motor is turned on and continues until it ...
1k views

Power = Voltage x Current

I understand the equation that Power = VxI. Due to the Joule heating effect, engineers prefer to keep V high and I low to minimize the heating losses. When I think of current, it is the number of ...
52 views

LED Wall neutral current problems

I’m running a film project that involve a huge Led wall. I have 1000 screens that can pull .6 amp each they are balanced for load on a 400amp 3 phase supply but I’m measuring the same current in the ...
57 views

Amplify the output current of an MCP4725 in order to drive multiple sensors

I want to connect the signal generated by a MCP4725 digital to analog converter to the heater of five sensors. The LA6500 works well to amplify the output current mcp4725 for one heater sensor. Can I ...
64 views

Understanding the safe operating area of a 1.7 kV rated MOSFET

I am looking at the datasheet of a 1.7 kV SiC MOSFET from CREE (C2M0045170D) which is attached here. I am under the impression that if I control the MOSFET using PWM, during the turn-ON period (ton=10 ...
72 views

Using current division to find voltage

I'm a beginner in electrical engineering. I am having trouble with this circuit analysis problem. It asks to simplify the circuit into an expression for $V_L$ in terms of $R, R_L,$ and $i_S$. ...
79 views

What is alternating current polarography (ACP)?

I am taking "RF Microwave Signal Chain & Network Analysis" webinar from Keysight. There is a slide there with acronym (ACP). I assumed it is alternating current polarography. I am ...
94 views

Fixing corroded contact surfaces on PCB

Looking at a Seagate HDD that no longer connects. The motor is running, but does not show in devices. The disk has production date is 12361 (2012-03-05). Before having a look inside I checked out the ...
140 views

How can this BLDC motor have constant torque over its RPM range?

I was going through this catalogue of BLDC motors for my EV project. I found two motors in it, one rated at 2.5 kW of peak power, and the other 6 kW of peak power. My questions are as follows: It is ...
172 views

What's the effect of the resistance added to the non-inverting input?

I'm trying to figure the effect of adding a resistance at the non-inverting input of a inverting amplifier. simulate this circuit – Schematic created using CircuitLab How can introduce it in ...
117 views

Why are the electrons coming back with 1V?

The current is in conventional flow , it enters the battery. Is it possible that the electrons that go out of the current source come back to it with 1000mV?
105 views

Mains A/C Current sensing

I am looking for a solution to detect de presence of mains current with the Arduino. I came across a few solutions but I think all of them have some serious drawback for this case: I have 8 power ...
107 views

Why does a fuse break before an LED?

Assuming the current passing is more than what both the fuse and the LED can handle, if electrons pass through the bulb first, would the fuse break first, or is it a matter of the LED requiring more ...
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How much current is available with a buck converter? (re: 20V/5A to 5V/20A?)

I've been trying to research this as much as possible but I'm still a little confused. If I'm using a PSU rated for 20V / 5A, can a typical buck converter output 5V / 20A? (assuming 100% efficiency ...
81 views

Frequency dependent amplitude of a current source in an .AC analysis in LTspice

In my LTspice simulation I would like to integrate a current source in an .AC analysis which has an amplitude that varies over the simulated frequency spectrum, e.g. something like \\$A(f) = {A_0 \cdot ...
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I am designing the thermal outline plane of this current amplifier ic in a 4 layer board using Eagle Pro. This board will be made using ENIG process. After spent so much time trying to understand in ...
68 views

Atx psu turns off [closed]

I have an ATX power supply from an old computer probably 10 years old. The psu has the usual black, red, orange, yellow wires for 0,5,3.3,12v . Besides these it also has pink for 5v, brown and orange ...
58 views

what is the real electrons flow of a current source diagram [closed]

what is the real electrons flow when a current source symbol drawn .In arrow way or other way
650 views

Long vs short wire when using DC

My knowledge of electricity is hobby level, maybe even less. In a powersystem that runs entirely off Direct Current, powered by a 600 mAh lithion battery, imagine the following scenario: ...
80 views

Connect negative terminal of a battery to Earth

I have a question about what happens in following experiment: Assume we have a battery with two Galvanic half cell, eg. a magnesium anode and a copper cathode. Since copper has higher electrode ...
29 views

Boost converter switch current computation verification

I need to have a boost converter in my design in order to provide 5V to the entire system. According to all datasheets I could gather, the total current of the board should not be above 1.5A. So, the ...
27 views

Ground fault measurement in low voltage DC project

I am playing around with a system to detect residual current in a 12v DC system. Considering using this sensor: https://sensing.honeywell.com/index.php?ci_id=49794 If I run the +ve from the battery ...
79 views

Current calculation - basic circuit

I’m just starting off, and I’m watching a series of videos about the basics of electric circuits. https://youtu.be/lf0lMDZVwTI As you can see in the the picture, the teacher solved the current of the ...
56 views

Measuring PWM controlled current with a microcontroller

I want to measure current using sensor MLX91220 which gives output in analog. I have battery that I charge and discharge via switching MOSFET and want to measure current on this grid. Problem is that ...
108 views

What is current steering and charge steering?

'Charge Steering: A Low-Power Design Paradigm' by Razavi. I was reading the paper and came across these two terms.I tried googling but did not get a proper result, I have no clue what these are. Can ...
78 views

LTspice: Can I simulate current generated heat?

I'm simulating a simple circuit with a resistance temperature detector. I want to know if it is possible to simulate the small change in the resistance as the current flowing through the resistor ...
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Boost with inverter, second harmonic current

I have a boost converter followed by an inverter to supply a load. The output frequency of the inverter is variable but relatively low (~50 Hz). The issue I'm facing is the second harmonic current (at ...
47 views

Achieve maximum power output of load with this transistor configuration?

How to achieve Maximum power output of the variable load with this configuration? I have tried to reduce the load, increase or decrease R43 & R49 but to no avail. Even if you try to increase the ...
40 views

Finding out the current needed to power a photography flash

I'm trying to find out the current needed to power a Godox MS300 photography flash (Official specs at the end of the page). I'm using the 220V version, and it says that at max power, the output is ...
129 views

Input bias current and offset current calculation for an LM741 op-amp

This is my circuit diagram: The bias current of the LM741 op-amp is 80nA. The offset voltage is 1mV. The LM741 has relatively large current offsets, voltage offsets and input bias. I calculated the ...
58 views

Inverter circuit (DC to AC) [closed]

Hi readers, above is an inverter circuit that converts DC to AC. How do I increase the output voltage and decrease the frequency to let’s say 60 Hz? Above pic is the voltage I measured at AC (Vout).
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Why is my switching frequency so abnormal?

I am using this Buck Converter 2A part. I am giving an input voltage of 3.3V to get an output of 1.2V for a switching frequency of 2.25MHz. I am giving different load currents of 0A, 0.2A, 0.5A & ...
46 views

Increase power of load in AC to DC converter

Hi readers, above is a ac to dc converter. I want to increase power output of the load and that's why I put the load resistance to be much lower than the series resistance(internal resistance). ...
51 views

Power absorbed by diode in simulation

This is a simulation in LTspice. The graph below shows the power vs time for diode D2. Is it a concern that in the first few microseconds, the power absorbed by diode is 500W? Is that a lot and will ...
99 views

Is this capacitor graph safe to be constructed?

Above is the power vs time graph of a capacitor charging & discharging in a rectifier circuit. It spikes between 350 W and -140 W, which is extremely high. However, the average is only 2.7158 W. ...
105 views

Hi readers, this is an AC to DC converter. I have been trying to build a power-saving rectifier by changing the capacitance for this specific load (20 ohms and it is a constant load) in order to ...
135 views

AC to DC converter circuit

This is an AC to DC converter. From what I have simulated in LT spice software, when the R1 drops from 1k to maybe 5 ohms resistance, the output is oscillating and no longer smoothing to DC. I have ...
58 views

Designing battery low indicator for a 3.7 V Li-Ion battery [closed]

I am looking for a solution to create an indicator for a li-ion 3.7 V single cell lighting red if the voltage of the cell is ≤ 3.3 V. SG3546 was an ideal option, but it looks that this chip is not ...
74 views

Resonance peak occuring in Bode plot of DC-DC Control Loop before the cross over frequency. Why?

Like, how does the resonance happen before the cross over frequency? Can someone explain the intuition behind it?
149 views

Output Impedance for Stability Analysis

I was reading this application note from Omicron. Output Impedance for Stability Analysis I was not able to understand how the output impedance is used to measure the phase margin of the DC-DC Control ...
210 views

Calculate the temperature rise in a wire due to current

An insulated wire, if I pass a current at a given voltage, what will the temperature rise be. Below is what I think I understand so far ... I'm assuming the insulated wire is a 5 m long single ...
48 views

Is this 240W power supply constant? [duplicate]

I want to buy this. However, I am not sure whether 240W power supply that I choose will efficiently power a 12 W device. Is the 240 W power supply constant or can it change depending on the power ...