Since all circuits have current adding this tag is rarely appropriate. Flow of electric charge - typically movement of charge carriers, such as electrons. Measured in amperes (A).
-4
votes
1answer
62 views
DC Current Regulator 24v [closed]
I am trying to connect solar panels to a battery and then add a grid tie inverter of 1 kW. If you connect the grid tie inverter directly to the battery it draws way too much current, gets too hot and ...
1
vote
2answers
119 views
Problems when sharing a battery between motors and radio in an RC car
Background
I am building an RC Car that I am trying to modify to control from an Android phone.
When I connect the remote control module as well as the car circuitry (servo & motor) to separate ...
0
votes
4answers
108 views
How input current affects circuit? Is it ignored?
All the examples I have seen so far, take the input voltage as-is and start calculating circuit current depending on on-board resistors using ohm's law etc.
Can you just ignore the original current ...
2
votes
2answers
1 views
Input impedance of Arduino Uno analog pins?
I'm using the ACS712 hall-effect based current sensing chip on some small robotic arm motors, and reading in the analog voltage with an Arduino Uno. I've had reasonably good results, but only after ...
4
votes
4answers
161 views
Can electronics be damaged by under-currenting it?
Someone just asked Can electronics be damaged by undervolting it?, so now I am going to ask under-current. Let's say something requires 10A, 12V, if I limit the current to 5A, could anything go wrong?
...
-3
votes
3answers
114 views
What works on 8-10 volts, 4 milli amps, and is not hardwired? [closed]
I want to know what is the smallest device that can work on a few milli amps? I know a NE-2 neon bulb works on less than 10 mAmp but on 90 volts at least.
I need to find a small device that:
...
2
votes
1answer
56 views
Frequency Scaling and current draw
I am trying to power a RPi of 4 AA's, and my mobile power device can only output limited current (500mA), but I can underpower my RPi by frequency scaling. Is frequency scaling and current draw a ...
0
votes
1answer
46 views
DC-DC converter maximum current rating
I am using an XP Power XP-IL1224S 12V to 24V DC-DC converter, does anyone have experience with the current rating of these kinds of parts?
The maximum current is rated as 84mA @ 24V, which works out ...
0
votes
1answer
71 views
Ground Fault Question Regarding a 3 Phase Circuit
I'm needing to design a 3 phase ground fault detection system for a 480V system. It will need to be able to trip when there's ground fault current >1A.
I have done some reading and it sounds like ...
-4
votes
1answer
94 views
How to find the current and Resistance?
Ok Everyone DownVoted! i am sorry about the diagram! So i Updated it
this is my new diagram:
simulate this circuit – Schematic created using CircuitLab
Then Now how to find I1? what is ...
2
votes
2answers
95 views
Can a too powerful battery damage a circuit? [duplicate]
I have an IOIO board, a 13V 10A Battery (when I tested with my multimeter). For the IOIO board, 5-15V, ~10mA is enough. Can a 13V 10A Battery do wrong to the board or is it okay?
3
votes
2answers
98 views
Ground vias on high speed PCBs
I know that if I use vias on high speed traces that I need to reduce the inductance effect of the via. So I will put ground vias next to these vias to help returning current. I have seen a picture ...
1
vote
1answer
48 views
Detecting Motor Overload
I want to make a circuit to indicate an LED if a motor is drawing too much current. (when the motor is stopped for example mud got stuck around the gears) I am using 9-12 volts to power my motor, and ...
2
votes
1answer
117 views
Calculating current in a simple circuit
I am new to electronics and am trying to figure something out:
I have a source putting out 12.6V and an unknown current.
I know that I can calculate current by finding the voltage drop over a ...
9
votes
3answers
135 views
Current produced by thermocouples
I can't seem to find an answer to this on Google.
Take a K-type thermocouple for example. The voltage produced is around 41uV/K. I'm wondering how this changes when a load is put across it. What ...
2
votes
3answers
140 views
Circuit that can convert current pulses to voltage
I have an anemometer which outputs current pulses. I can't take it apart but I know there is a phototransistor and LED in parallel shining through holes to it. I was told that with 30m/s wind there ...
2
votes
1answer
149 views
current controlled current source
Objective
I am trying to build a gain-of-1 current controlled current source (current mirror) that is less sensitive to resistor value variation. The designs i have been making are highly resister ...
2
votes
2answers
68 views
Measuring the current of a DC circuit
I'm creating a set of modules that can be daisy chained and hooked up to a master controller unit. I'd like to have a display on the master that shows the combined current draw of the modules in ...
1
vote
1answer
44 views
Values in a solar array
My dad had just bought a solar array of 4kW together with an inverter, a kaco powador 4400.
The array is now running and generating electricity. I am trying to understand how it all works, but ...
1
vote
0answers
68 views
Why does my bluetooth dongle use more current when paired then when idle?
I have a bluetooth dongle which is connected through USB to my PC. I wanted to measure the current drawn and hence I connected an ammeter in series with the 5V line and am measuring the current. I ...
1
vote
1answer
88 views
Amperian loop to measure solenoid's magnetic field
My textbook proves the formula \$B =\mu_0In \$ for a solenoid by taking a rectangular Amperian loop as shown here:
The problem I see with this though is that it only takes into account the ...
4
votes
4answers
266 views
Is current the same coming out of an IC as it was going in?
This is my first diagram so keep that in mind. I've come up with this circuit because
I've got some 74** series ICs and I want to be able to make them work. This example is
a simple AND gate with ...
0
votes
2answers
97 views
Negative and positive cycle of AC current, Half wave rectification and Full wave rectification
Can someone please explain to me precisely what the negative and positive cycles of AC current are, what full wave rectification is and what half wave rectification is?
1
vote
2answers
117 views
Detecting the over current and cutting off the supply
I have a load which draws current from the source that is less than 500mA. If by any chance, the load becomes heavy and starts drawing a current which is more than 500mA, this over-current should be ...
1
vote
1answer
77 views
How does one compute the ripple currents seen by a boost converter output capacitor?
Suppose one is designing a boost converter, with a known maximum current load, and a known inductance:
The ripple current seen by the output capacitor is critical. If that current is too high, the ...
3
votes
1answer
129 views
How does one compute the ripple currents seen by a rectifier filter capacitor?
Suppose one is designing a full-wave rectifier bridge, with a known maximum current load, and a known input inductance. Assume three-phase for this example, though the same concept applies to ...
3
votes
2answers
185 views
Do I need to use a resistor with a microswitch to limit current for an Arduino Uno?
I'm using an Aruduino Uno to control a small robot and I'm starting to add micro-switches as bump-sensors. I know that when I'm creating a circuit with LEDs I need to use resistors to limit the ...
3
votes
1answer
89 views
Transistor varies with Temperature
My questions pertains to the \$ \beta\$ value of a transistor. On page 162 of this book, it says that \$ \beta\$ increases as temperature of the transistor increases. But it doesn't explain why. Can ...
0
votes
1answer
138 views
12V for a 10.5V netbook? [duplicate]
I cannot find a clear answer to my question on the web, so I hope you can help.
I have a Sony VAIO VPCX11s1e/b netbook (11.1 in.) with a 10.5V input for a powersupply.
I want to use it with a solar ...
1
vote
2answers
76 views
Decreasing voltage without decreasing the current
I have got two 12 V 7.2 Ah lead-Acid batteries, which are connected in Series (26 V after charging). The batteries are connected to a step-up / boost module which have to be 2 V higher than the input. ...
0
votes
0answers
75 views
How to sum or calculate voltage or current harmonics component that are in parallel ?
Recently I measured voltage and current harmonics in coal mining industry. But they only have Power Quality Meter with limited current clamps (not big enough for the PCC(point of common coupling)). So ...
1
vote
2answers
125 views
Simplifying a circuit to measure current
So I'm to calculate the current in the places I put the ammeters in (yeah, I reckon one of them is turned around :)):
And while I can calculate such things for series or parallel circuits, I was ...
2
votes
1answer
51 views
ULN2003A rating
I am confused about what this statement means:
Each channel rated at 500 mA and can withstand peak currents of 600
mA.
Does it mean that the ULN is capable of driving up to 500 mA per channel ...
0
votes
2answers
183 views
Inexpensive multimeter for integrated current measurement
I'm building a simple circuit with an Arduino Nano board, which will read signals from a Hall sensor and periodically send pulses to a small 5V solenoid. I'll drive it from 6xAA batteries in series, ...
-6
votes
2answers
136 views
Battery with most mAh that outputs between 1 and 1.5v? [closed]
I am looking for a rechargeable battery between 1 and 1.5 volts that can provide this voltage for the longest amount of time (most mAh). Any suggestions? Thanks.
3
votes
2answers
133 views
Mathematical approch to measuring current, voltage and resistance of mixed series and parallel
If there is a circuit like the one below, where all resistors are 1k ohm, how does one determine the currents? The voltage sources are all 10 volts.
The problem I am having is that I do not know if ...
8
votes
2answers
227 views
Wilson current mirror
I built a super wilson current current mirror. The Iin is 4-20mA at 24Vdc. Iin to Iout accuracy was a really bad 5%. I put 100 ohm resisters on the source to ground, and that helped a little. How can ...
1
vote
2answers
150 views
Fix the Problem for Shunt Resistor due to Temperature & Current Sensor
I am trying to build a current sensor here. My original thoughts starts from this paper [real-time current-waveform sensor with plugless energy harvesting from AC power lines for home/building ...
1
vote
1answer
142 views
How does current split in a circuit?
I'm redesigning a board that has a lot of peripherals attached to a SOC. These all use different voltages. Board is powered with 12V,1A
Most peripherals are connected like this:
RJ45 <-> GigE phy ...
4
votes
1answer
82 views
How do I calculate the supply current for a zynq 7010 chip?
I have a Zynq 7010 chip, and the current requirements in the datasheet confuse me a lot. Could someone explain how to determine how much current I'll need to supply to each rail?
...
1
vote
0answers
59 views
dc machine with brushes covering more than one commutator segment
i'm a bit confused with the current that flows in a wave armature winding of a dc machine. In a wave winding, there are two current paths, right? what happens when the brush covers more than one ...
6
votes
2answers
263 views
Is there any way to boost DC current?
I'm designing a circuit to charge mobile battery. My source is giving a DC output of 15V, 100mA, whereas I need DC 6V, 450mA for charging. Is there any way to boost DC current?
1
vote
0answers
67 views
Testing the Amp ability of a copper wire in an automotive environment
A question posed on a forum for the pico scope relates to testing of the wiring for a load bearing circuit. For example a circuit with an electric motor, lamp, heater element, fuel pump, etc. They ...
1
vote
3answers
148 views
11A trace width
Using this PCB Trace Width Calculator the external tace width for 11A (default settings) is suggested as 8.21mm.
Is this acceptable? I was expecting something bigger, and just wanted to check that ...
2
votes
1answer
63 views
NXP LPC1343 GPIO questions
I am an embedded SW developer who wants to get more familiar with HW design. I have an LPCXpresso board with an LPC1343 on it. I want to build some circuit around that. I thought I'll start by finding ...
11
votes
4answers
177 views
Is \$I_e = I_c\$ for phototransistors?
Due to the base current, in a common emitter circuit the emitter current is a bit higher than the collector current:
\$ I_e = \dfrac{1+\beta}{\beta} I_c \$
I was wondering how this is for a ...
2
votes
2answers
86 views
Battery Charging Current Determination
When charging a battery using a solar panel, or even another battery, how is the current flowing through the battery determined?
Will the internal resistance of the battery draw a certain amount ...
4
votes
1answer
148 views
Current source with IGBT
A simple current source using a bipolar transistor uses the voltage over an emitter resistor as feedback of the current. The current is given by the base voltage, the \$U_{eb}\$ of the transistor, ...
1
vote
0answers
341 views
ACS714 5A AC Current Sensing arduino
hey guys i just got my ACS714 -5 to +5A IC i am new the current and voltage sensing i googled for tutorials on ACS714 5A but couldn't find a suitable tutorial with AC sensing.
I got the code below ...
3
votes
1answer
225 views
Shortcircuit protection with PNP
R1 became RS
R2 bacame R
1)Is this a correct shortcircuit protection?
2)What is the max current that can flow before the transistor enters in saturation?
