Tagged Questions

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

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0
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2answers
26 views

Constant current power supply and 2 LED - series or parellel?

I have a very limited understanding of how current works in parallel or in series. I am trying to connect a pair of LEDs to a constant current power supply (1200ma) in which the power supply ...
1
vote
1answer
128 views

What is meant by output Leakage Current?

Is output Leakage Current= Output Current - Input Current? I encountered the term in a datasheet of the L9938 driver.
1
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2answers
38 views

calculating the input current that can be taken by an Operational amplifier

Is there a way to calculate the input current that can be taken by an Operational amplifier, if we know its input Bias and input offset current?
0
votes
2answers
69 views

Transformer core maximum power

so i am an EE undergrad, and i am wondering if and how exactly does a transformer core limit its power capacity. From my understanding, the rated power of a transformer is due to the current carrying ...
2
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1answer
20 views

Standing Wave ratio vs frequency in power transmission lines?

What is the relationship between Voltage Standing Wave Ratio (VSWR) and frequency in context of transmission lines?
0
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1answer
37 views

Solar cells, current limited by smallest cell?

I've read on a bunch of different sites that: "You also do not want to mix different sized cells together because the current or AMPS of your solar panel will be limited by the smallest cell in the ...
1
vote
4answers
291 views

what could be the visualization equivalent of the resistors in series?

Why do resistors in series add-up? Is there any visualization equivalent of that? I have in mind electrons as cars driving on the highway, now a resistor could be a narrow spot (R1) where cars are ...
5
votes
3answers
145 views

How to tackle regenerative current in my H-bridge

I am using 2 of the following H-Bridge to control 2 x 24V 350W electric scooter DC motors. The power is from 2 x 12V 12AH SLA batteries in series. EDIT: These are the entire schematic and PCB ...
0
votes
2answers
64 views

What is max current for goldpin connectors? [closed]

I'm designing a circuit which consists of two blocks on the same PCB. For testing I'd like to have an option of bypassing the second block and connect the first one to the output. The standard ...
-4
votes
2answers
75 views

Separating the currents [closed]

I got a big problem that I have to put these to motors together like this but they have same working voltage but different currents and that's what makes the second motor doesn't work correctly ...
2
votes
3answers
270 views

Current calculation in circuit

Please show me the steps to calculate current going through R1, R2 and D1 Led (Green color LED), when I tested this circuit through a multimeter it showed as 2.5ma across R1 and R2 but 0ma across D1, ...
0
votes
1answer
31 views

Minimum limit for current and maximum limit for voltage while calculating power

I have a brushless Motor then i am using in conjunction with a ESC, powered by a Lithium Polymer Battery(3S 1300mah). I just got a new Lithium Polymer battery (6S 15000mah) from a friend and am ...
1
vote
2answers
98 views

How can I work out if a cable can take a momentary current spike?

In this video here, almost 1000A is being run through a 10mm steel bar, and after a minute or so, it melts. https://www.youtube.com/watch?v=YzZ3aJqmT-M So in terms of charge, 60,000C applied for 1 ...
1
vote
3answers
171 views

Why can't different current sources connect in series?

I've posted different question similar to this, yet still struggling to understand the theory. So here is another attempt to understand as to way two power sources(with different currents) connected ...
0
votes
0answers
78 views

LED and constant current [duplicate]

Want to build a grow light for plants using a full spectrum, now regarding the electrical side of it. using a constant current "CC" power supply, what kind of driver would I use to vary the amps to ...
-1
votes
1answer
50 views

Multiple power sources, each for a certain purpose? [closed]

In a circuit, there is somewhat of a symmetry of power sources being connected together. If they are of equal voltage they would be connected in parallel increasing current at the same voltage. Or if ...
7
votes
7answers
2k views

Transistor - Why does amplification happen before the transistor and not after?

I know this is a noob question but I just can't find an answer for it on google search results. Well my question is basically this: How come the amplifying occurs before the transistor [red line] ...
0
votes
1answer
68 views

How to Modulate Current without an Arduino

I am looking to turn current "on" and "off" extremely fast without the use of an Arduino. With an Arduino, I understand I would be able to do that in code. However is there another way of doing this? ...
0
votes
0answers
26 views

Can I power a IOIO-OTG board with the regulator on a Koala Protoboard?

I'm building a small device which uses a IOIO-OTG board. I figured I would mount my components on a Koala Protoboard along with the IOIO to use the recharging/usb regulator circuit provided on the ...
0
votes
1answer
58 views

Calculating the current

I recently got a power supply schematic for my project, but for the rest of the project I need to know how much current is being used on the AC input and I don't have the completed board yet to test ...
2
votes
0answers
34 views

Connecting home elliptical trainer to TV power

I'm attempting to use a TV addiction to help motivate an exercise routine. To do this, I am going to connect an elliptical trainer to the power of a television set (flatscreen). Here is my plan: I ...
0
votes
2answers
58 views

Different current ratings in series?

A circuit that has 3 power sources connected in series, where V1 = 0.2A at 20V V2 = 0.05A at 5V V3 = 0.2A at 20V Diagram: simulate this circuit – Schematic created using CircuitLab ...
0
votes
0answers
41 views

Reference Current for many LED drivers

I am developing a project in which I need to control many LEDs simultaneously. Therefore, I am using many TLC5940PWP LED Drivers (which are driven themselves by small microcontrollers connected by an ...
0
votes
1answer
38 views

Solar Panel Cellphone Charger - Not Enough Current?

The Materials : 1) 3 X 1.5W 6V Monocrystalline panels @ 320mA 2) DC-DC Variable Voltage regulator 3) 3 X 1N4001 Diodes The Problem : - I have connected the panels (which give about 203 mA ...
1
vote
1answer
90 views

Can one be electrocuted when cleaning a light switch? [closed]

Light switches are allegedly some of the dirtiest spots in a house, and cleaning them is recommended in many articles. However the safety angle doesn't seem to get coevered. The only thing I could ...
5
votes
2answers
74 views

Why pulsed drain current is higher than continuous drain current in MOSFETs?

Why is pulsed drain current higher than continuous drain current in MOSFETs? In MOSFET data-sheets, pulsed drain current is much higher than (by at least 2x) continuous drain current. What is the ...
0
votes
0answers
69 views

Capacitors not keeping charge as expected

I have a voltage doubler charge pump that is used to provide voltage over an IR LED for a short pulse, I also have a driver circuit for the LED to sink the right amount of current that I am requiring. ...
1
vote
2answers
186 views

Voltage Current and Circuit

What does short circuit and open circuit mean ? I mean practically what does short circuit & open circuit means?
0
votes
1answer
66 views

What happens if we swap these two components?

So, in what looks like an attempt to explain mesh currents, my book has the following diagram: Then it proceeds to convince us of the veracity of several equations. The first of them makes sense: ...
0
votes
2answers
93 views

Current reading, how does it work?

For a project I'm using an Arduino to drive a motor using a special pcb. In this board there is also a way to read the current drawn by the motor. Although I have the schematic I'm not 100% how this ...
0
votes
1answer
44 views

Current usage with multiple PWM controlled motors

I have a circuit that can use 25 A of current max, it is on a 25 A fuse. I am looking to control 4 DC brushless motors using ESC's. The trouble is that the motors are rated at 7A max current. I know ...
1
vote
1answer
81 views

Where does the current in a Dickson Charge Pump come from? Does the oscillator/PWM pin of a microcontroller also source current?

Well, I am making a small circuit which looks like this: When simulated, the load current gets up to about 200-280 mA no problem, so I want to implement this circuit in real life. My only problem ...
-2
votes
1answer
54 views

Current overlap in Inductive Smoothing?

I have the following circuit implemented in the lab : And the output was : Can anyone explain why the current overlaps here ? I can't make sense of this.
0
votes
1answer
60 views

Is accelerometer taking as much power (current) as it needs? [closed]

I want to connect accelerometer to an oscilloscope. I have 3x AA rechargable batteries (2550mAh). I was told that e.g. microcontroller knows how much amps should it take and it wont burn if I ...
1
vote
2answers
141 views

Current capacity of wires

So this question stems from a previous question. Here Where from several tables one can see that the maximum current (Imax) is proportional to \$1/R\$ where \$R\$ is the resistance. (Or that ...
0
votes
0answers
47 views

Datasheet for Keyes IR Transmitter (KY-005) wanted

Can someone help me find the datasheet for the Keyes IR Transmitter (KY-005)? I know how the pins work, I just need to figure out its voltage drop and how much current should go through it. Thanks! ...
3
votes
1answer
81 views

What external factor could cause increased current draw?

I have a metal cased device powered by 2x 1.5v AA batteries with a standby current draw of 19.7 microAmps. If I then cause a build up of static by shuffling across a synthetic floor and touch the ...
-1
votes
0answers
36 views

Need 2.1 Amps from a USB wire for my lighthing conector [duplicate]

I have been working into an ipad Conector, that seems to work FINE its plugged to a 5v 12A switching power supply, this goes to my PCB where it has up to 4 outputs, each output for 1 ipad Air, up to ...
0
votes
3answers
54 views

Current Source Circuit Internal Impedance

So I've been learning about current source circuits - this one in particular. I'm told that an ideal current source should give out the current no matter what happens to the load. But it should also ...
0
votes
3answers
86 views

Diodes block voltage?

I understand the basics of a diode, a diode allows current to flow in only one direction, but how? By blocking any opposing voltages source so that no current can flow in opposition? And of course, a ...
0
votes
1answer
75 views

What is the path taken by the back emf current?

! Where will the current flow through? If ON current(back emf "current") will loop through A B and C If OFF current will(back emf "current") loop through x y and z
0
votes
0answers
62 views

Calculate current in an series RC circuit with a DC square wave source?

Am still a noob in electronics so bare with me, In the image bellow how is the voltage drops found and the current in the meters, what is the formula? and if instead of a capacitor an inductor is used ...
1
vote
1answer
50 views

LEDs in parallel, strange current consumption

I just wired a blue LED on a breadboard with the anode to an Arduino Uno's 3.3V rail and the cathode to a 220 ohm resistor to ground. Then I measured the current consumption using my Fluke 87-V and it ...
1
vote
1answer
56 views

Current Leakage calculations regarding shock hazard. A complete picture?

There is a quantity called current leakage which has always confused me. By reading various definitions, it seems to be the current flowing through the ground circuit of a device (whether this be an ...
0
votes
2answers
113 views

Does current flow stop when a capacitor is fully charged?

If I take a 1V battery and a 1 farad capacitor and a bulb and connect them in a circuit. Then will after the capacitor gets charged (not fully charged as that is impossible) will the bulb gradually ...
0
votes
1answer
48 views

Effects of C Rating on Battery Life

A polymer lithium ion battery is rated at 3.7v, 6600mAh and a maximum discharge current is specified at 3.3A. I take it this means the battery can be discharged at 3.3A and last for two hours since ...
0
votes
1answer
50 views

RGB LED Strip - several question from newbie

I've just bought 5 meters long 12V analog RGB LED strip and I'd like to turn it on! There're 60 LEDs per meter so, totally 300 LEDs and each LED consumes 20mA. Here're my questions. From internet ...
0
votes
1answer
79 views

Measuring Current in 12V DC Fan

I am trying to measure the current of a DC computer cooling fan (Intel E18764-001) at various volts. Its rated specs are: 12V 0.20A. Check it out here. So I am suspecting that this is telling me: ...
1
vote
3answers
182 views

Direction of current through a circuit with multiple batteries

So I've got a bit of a problem trying to understand this circuit in my physics book. If current flows in the direction of the three arrows (I1, I2 and I3, couldn't find a way to name them) how can ...
0
votes
1answer
32 views

What should my priorities be in designing a home generator?

I have a few basic electrical engineering questions. My purpose is a home wind/ hydro electric project to sell back to the grid. My questions are these: 1. Which generates greater power: running at a ...