We’re rewarding the question askers & reputations are being recalculated! Read more.

Questions tagged [current]

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

322 questions with no upvoted or accepted answers
Filter by
Sorted by
Tagged with
6
votes
1answer
131 views

Voltage Controlled Current Source - help needed

I am designing a voltage controlled current generator for the currents in a range from 0 - 2.5mA. The load resistance is within the range of 0 - 5k Ohms. I decided to go with difference amplifier ...
4
votes
1answer
358 views

Adjustable High current source (40A?)

I a looking for a schematic of a circuit to built an adjustable current source capable of delivering up to 40A. I am building a battery with 18650 cells. These cells will be individually fused ...
4
votes
1answer
125 views

Can this example be used for explaining the effect of lamination on power loss in a power transformer?

I'm trying to demonstrate to a group of people how a lamination of the transformer core reduces the power loss due to Eddy currents by not using any complex math. I start with a non-laminated core as ...
4
votes
2answers
410 views

Managing reverse currents using MOSFETs

I'm planning to use a chip with two 5V output pins to provide power to two systems: a MCU (attiny85, operating voltage: ~2V - ~5V) and a USB device (input current: 3A). On top of that, I'll have an ...
3
votes
1answer
76 views

Problem with high current draw in circuit design

I am working on a project where I've taken an LDC1612evm (inductance to digital converter) and removed the connected micro controller portion to communicate with a TM4C123G LaunchPad via I2C. I have ...
3
votes
0answers
95 views

How to distribuite high current in multilayer PCBs

I'm designing a 150Amp controlled rectifier and I'd like to know how to distribute the current using a multilayer design. Currently, I have a 4 layer design containing: Top Layer: 6oz, Vdc+ and Vdc-...
3
votes
1answer
1k views

Current capacity of copper wires in vacuum

I’d like to know the current carrying capacity of copper wires in vacuum. The current plan (NPI) calls for sending ~3 amps through the vacuum space of a cryostat. Has anyone done this? Have any ...
2
votes
0answers
46 views

LED Matrix creation using resistors & MAX7219

I've been attempting to create my own LED matrix, but now I've plugged it all together I'm getting some unexpected LED's lighting up, it seems some are getting power when they shouldn't (not very ...
2
votes
2answers
52 views

Switches for current source

simulate this circuit – Schematic created using CircuitLab I1 is an wilson modified current source by 4 pnp transistors. SW1 and SW2 are doubts. When SW1 is open, SW2 must be closed and vice ...
2
votes
2answers
49 views

What happens if the load (connected to the output of the circuit) disconnects suddenly from Arduino/ESP32?

My circuit (that contains esp32 with few current and voltage sensor) is connected to 9Ah Battery (with BMS), where the load gets connected to see the discharge rate of the battery. There are times ...
2
votes
1answer
58 views

Measuring integrated current

I want to measure the amount of light striking a photodiode in a specific time window (about 1ms). In this window, we get \$10^6-10^7\$ photons, which get converted into electrons with about 80% ...
2
votes
0answers
81 views

Is there a limit on the current carrying capacity of a wire?

Obviously, for continuous current there is - the melting point. If it is superconducting, the field strength at which it quenches. OTOH if we specify a pulse of arbitrarily short timescale in order to ...
2
votes
0answers
213 views

Mistake in published paper about magnetic levitation?

As I was reading through this paper: Nonlinear Model & Controller Design for Magnetic Levitation System, I stumbled cross section 3.3 which I could not follow. Summarizing section 3.3 Non Linear ...
2
votes
0answers
168 views

Current derivative in RLC circuit

How to find the current derivative(di/dt) at t = 0+ in the first loop?
2
votes
1answer
68 views

Does it make sense to use differential ended inputs to measure current signals with shunt resistor?

If I use 500 meters 4-20mA current loop in an outdoor environment, does it matter whether I use single ended or differential ended data acquisition inputs? I know that for voltage signals ...
2
votes
0answers
586 views

Improved Howland Current Source not providing less than 1mA

I've learning a lot about op amps and constant current sources lately. I've implemented the above Improved Howland VCCS. Found it on page 6 of TI's "A Comprehensive Study of the Howland Current Pump": ...
2
votes
0answers
555 views

Spark minimum current

I know from the title may sounds wired. But it makes sense to me at least for my restricted knowledge of high voltages. I'm always working with low or house voltage as well as this question may refer ...
2
votes
0answers
187 views

comparator input latches high?

I am using a a TI TLV3202 comparator (U2B) with a bridge circuit as shown in the schematic below. It is followed by a DG4157 analog switch. This is related to this question I had asked earlier. ...
1
vote
0answers
105 views

Is there a derivation of the Early effect?

I can't seem to find a derivation of the following equation: $$I_C=I_Se^{\frac{V_{BE}}{V_{T}}}\left(1+\frac{V_{CE}}{V_A}\right)$$ Is there a way to derive this equation? Edit: The equation ...
1
vote
1answer
35 views

Get expressions of E and H fields at a boundary from expression of surface current - Pozar ex 1.11

I am bringing whis question because, even though I have the solutions manual from the exercises of the book "Microwave Engineering 4th edition", by David M. Pozar (one of the Bible books for microwave ...
1
vote
0answers
37 views

LTC3112 undefined behaviour when power supply reaches current limit

I am getting a behaviour of LTC3112 that I do not understand. I am using it very close to the schematic recommendations in the datasheet. It works perfectly fine until my power supply (TOE 7610-60) ...
1
vote
2answers
71 views

Current flowing in an open circuit to make it the same voltage

I've tried to research this answer for quite some time but i'm struggling to find a proper answer. I think my question falls between antenna theory and batteries. So in a dipole antenna we supply a ...
1
vote
1answer
55 views

Voltage controlled current source doesn't have constant current

simulate this circuit – Schematic created using CircuitLab I have this circuit for a voltage controlled current source, but it isn't working.The transistor is a Darlington.The circuit is ...
1
vote
1answer
75 views

Need help with 2 Transistor Current Limiter Circuit in LTSpice

I am new to LTSpice. I have attached a picture of my circuit below: The goal of the circuit is to provide current to the R1 until It is too high. Then the BJT will activate, shutting the FET off. ...
1
vote
0answers
57 views

Thevenin Termination Current Calculation and Iol/Ioh

I am calculating the current draw for a thevenin termination and am having issues with the Iol and Ioh from the datasheet. From my understanding, when the source goes high (Voh), then Vtt (dest input ...
1
vote
1answer
52 views

Current source for high current LED driver- 24Vdc/max:16A

I am working on designing a current source for a LED driver, which can work up to max:16A, as long as stays On less than 500msec. Actually, the leds circutry is a Dome-light which is divided in 4 ...
1
vote
0answers
58 views

Understanding a ZVS Oscillator in-depth

For a project I've been building, I've been using the (overused) ZVS oscillator that can be found online. So far it's been working great transferring power wirelessly, but I'm interested in ...
1
vote
0answers
62 views

Reducing Current?

Having a problem with my EV a converted Fiat 500. The conversion is made with part from companies that dont exist any more, so it is hard to get information about them. The car have two batterybanks ...
1
vote
0answers
56 views

What can I add to a DC circuit, to limit the voltage to 24V and current to 16 amps?

I have a battery pack that can put out around 25V and 20 amps, but it needs to be limited to 24V and 16 amps. Update: This is a follow-up to my question from yesterday: Protected 18650 batteries ...
1
vote
0answers
113 views

High pass shunt filter

I have a DC motor, which is used as an electromagnetic brake. However I want to leave certain frequencies uninhibited, so I thought this should be possible by adding a shunt filter on the DC motor ...
1
vote
1answer
149 views

Resistor values on a 12v 10a circuit with LT3045 LDO

I am currently working on a project that aims to provide 12v 10a in the final output. I am quite new to EE and wasn't quite sure if I have choose the correct resistors value as highlighted in the ...
1
vote
0answers
65 views

Increasing output current from ZVS driver

I bought the ZVS driver as shown in the picture below: After connecting a flyback transformer, I tried measuring the voltage and current at the output. The open circuit voltage is about 12KV. To ...
1
vote
1answer
110 views

Reverse Current leak Battery+Diode in parallel

on my design, I am using two coin batteries in parallel and each battery has a Schottky diode in series to block the reverse current, in theory, it will avoid the higher potential battery "charge" the ...
1
vote
0answers
144 views

Why the opposite of the passive sign convention is not the active sign convention?

Studying the fundamentals of circuit theory, I was reading the Wikipedia article on the Passive Sign Convention and found out about the Active Sign Convention (ASC). After searching many introductory ...
1
vote
0answers
56 views

Current splitting in nA,pA range till 100 kHz frequencies

This relates to my previous question of current splitting. Current splitter/divider in nA/pA range possibilities I read about some circuits on current copying (current conveyor). However, the ...
1
vote
0answers
123 views

Differential Amplifier with TLC272 vs TL082

I have an LM2576-adj configured to step down 12V regulated output from a wall wart to around 5V-ish (see schematic). On the 5V output I have a 0.1 ohm sensing resistor (Rsc) to measure the output ...
1
vote
0answers
48 views

Simple circuit to sense current drop and apply current to a separate circuit? Trouble with backup dashcam triggering from taillight

Sorry I have very little knowledge of EE but I feel like there must be a simple solution to this. I purchased a mirror dashcam with backup camera function. Backup camera is supposed to be triggered ...
1
vote
1answer
54 views

How to find current through series of potentiometers, and if it is safe for potentiometers? (Arduino)

I have 9 potentiometer with the specs: 10k Ohms and 0.5W I'm using an Arduino Mega, and using it's 5V port output to power these potentiometers in series, and I saw online that the max current this ...
1
vote
2answers
150 views

Battery failing. Oscilloscope?

The question is - is there an inexpensive oscilloscope I can use to measure DC voltage and current to see why my battery pack is failing to power a DSLR? In order to take long time lapse photos with ...
1
vote
0answers
46 views

Voltage drop on power bench supply for channel being off

If I measure voltage drop between terminals of my bench power supply (spec) I get -15 mV when channel output is turned off. Why it is not reading 0? I believe it's due to internal impedance of the ...
1
vote
0answers
58 views

Off load voltage in npn transistor as a switch

There is transistor tutorial on sparkfun.com (https://learn.sparkfun.com/tutorials/transistors/all). I am wondering why there is 1.3 V drop depicted across the LED1 on the picture, since when the base ...
1
vote
0answers
198 views

Finding Current in Parallel RLC Circuit with 2 voltage sources?

I've spent sometime learning about step responses for series/parallel RLC circuits, but this problem takes things a step further, since C seems to be in parallel with a series combination of RL and a ...
1
vote
0answers
255 views

RL Circuit Analysis with 2 sources, how to find current of resistor?

I've been tackling some problems related to natural and step responses for RL & RC circuits, but I think I've hit a major roadblock for this RL circuit. I'm trying to find the time constant and ...
1
vote
1answer
94 views

Low current rs485 and wake up

I have the following question: I have to do a network of devices based on MCU. This network in a RS485 and the device is battery powered. For save the battery I put in sleep mode the MCU and I ...
1
vote
1answer
49 views

Load current computation of complicated resistance network

I'm reading Electronic Principles 6th edition by Malvino. Problem 1.28 describes a network of resistors that I would like to know how to solve mathematically instead of experimentally (as described in ...
1
vote
0answers
110 views

Power consumption measurement on the bench

I've been using the Atmel Power Debugger to sort out power consumption issues on some µController based circuits... and have been pretty pleased. Unfortunately, it's limited to a maximum of 5.5 volts ...
1
vote
1answer
66 views

Substation grounding

I am trying to understand a grounding system for substations, fault current is something I am not getting. For example, for a small substation with some transformers, if there is a fault in the system ...
1
vote
0answers
93 views

How to calculate the output voltage of the mirror circuit?

Please refer the following circuit added. Output voltage (Vout-A) is measured as follows, Following is the way I have started analysis: Krichhoff's voltage law around the loop ( R12 -> R3 -> V_BE(Q2)...
1
vote
1answer
67 views

How do I determine the unknowns for this equation?

Suppose a series RLC circuit in series with a 12 V battery and a switch initially opened. R = 100 Ω, L = 100mH and C = 10uF. L and C are initially discharged. A t=0 the switch is closed. I want to ...
1
vote
1answer
147 views

Nest Protect gen 2 battery to POE

Hey all i am looking for some advice in how to go about my project with a Nest Protect gen 2. In my home i have ran cat6 wire to all 3 locations that require a smoke detector. These cat6 cables are ...