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

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0answers
9 views

Saturated Transimpedance Amplifier Issue

I am using a transimpedance amplifier with a BP104 Silicon PIN photodiode to receive incoming pulses from an infrared LED with a frequency around 100 kHz. Here is the relevant part of my schematic: ...
0
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1answer
25 views

Find four current mesh

I have to find the 4 current mesh in this circuit V1= 12V R1= 1/12Ω R2= 1Ω R3= 1/3Ω I1= 6A R4= 1/3Ω R5= 1/2Ω R6= 1/13Ω I2= 6A I tried a source transformation and got this I3= 144V R1-2= ...
1
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4answers
36 views

Current limiter for NiMH battery charger

I am trying to learn about electronics by making my own MCU controlled battery charger for standard AA 1.2V NiMH and NiCd batteries. The supply voltage is 5V from a USB battery pack. I did a lot of ...
5
votes
2answers
405 views

What are Guard Rings?

I have heard about Guard Rings many times, and I know they are supposed to avoid currents in places where there shouldn't be no currents, but I never found a good ...
0
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1answer
58 views

In any circuit we can always control the input power? [on hold]

In any circuit, we can always control in voltage and current? We can stabilize them any value we need, given a good power source? Also, we can increase voltage in a circuit without changing current ...
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0answers
46 views

Minimum AC voltage that causes nerve damage?

What is the minimum AC(50-60Hz) voltage that can do harm/nerve damage? I know that a few hundred volts (even 100?) has been documented to cause nerve damage that resembles a crush injury. I also know ...
1
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3answers
135 views

What happens to a DC current at the end of a wire?

This question might be a little more appropriate for the physics stack, but I'd like to test the water here first. I am just getting into electrical engineering, and as I go along, certain aspects ...
0
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1answer
33 views

Calculating capacitance required for a pulse duration of time T using a class AB amplifier

Firstly I apologise if this question is similar to another one I asked a while ago. But, as you will see, this is question is slightly different. I have an amplifier which is a common emitter driving ...
0
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4answers
72 views

Replacing adapter with batteries?

I have some device with ac/dc adapter [9v, 500mA], and I want to replace the adapter with batteries. If I used [6 * 1.5v] battries, is that acceptable? do I have to worry about the max current of the ...
-2
votes
2answers
145 views

Is it possible to carry over 20MW? [duplicate]

Is it possible for a series of conductors carry massive currents(100 kA) at voltages over 100V? Assuming there is massive cooling. How can power plants carry MegaWatts of power?
2
votes
1answer
44 views

How do variable current limiters work in power supplies?

Bench top power supplies often enable you not only the set the voltage, but the maximum current. How do these bench supplies provide this variable current?
-1
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0answers
49 views

Stable current?

A large conductor that carries massive amounts of current at extremely low resistance(micro-ohms), now back EMF is induced that is really large. Let assume V = 0.2 volts and -V = 100 volts, and I ...
-1
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0answers
23 views

drift and diffusion

My question is about drift and diffusion current.In a semiconductor diode no "bias" condition diffusion is present and due to transfer of charges due to diffusion depletion region created and then ...
2
votes
3answers
97 views

Define this music-related terms with electrical terms [closed]

I have a somewhat bizarre question, I don't really understand this musical concepts and I think that some Electrical engineering could help in this case, especially with the analytic phase. Assuming ...
5
votes
1answer
232 views

Does MOSFET let current flow through source to drain as it allows it from drain to source?

Does a MOSFET allow current flow in reverse direction (i.e.; from source to drain)? I made a Google search, but couldn't find a clear statement about this matter. I have found this similar question, ...
0
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2answers
81 views

Can the output of two 15-amp motor drivers be hooked up in series to achieve a 30-amp tolerance?

I had a cheap 15-amp motor driver that I bought on eBay. You can see product details here. I was planning to use this motor driver to power my robot, which uses two 24v wheelchair motors. Then I ...
1
vote
1answer
50 views

How my ac-dc adapter gives constant voltage and current? [duplicate]

I have multiple ac-dc adapters, one with variable voltage and the others for electronic devices. written on them they give specific voltage and current, How come? Doesn't the current change with the ...
1
vote
2answers
66 views

Can i use a power supply that supply slightly higher current than the rated current from my dc motor? [duplicate]

I got a 12v ,0.9A dc motor.Currently i got two 12v dc supply which borrowed from my friend.The current of the 2 dc supply is 1.0A and 0.5A. Is it safe for me to use the higher current supply from 12v ...
4
votes
3answers
203 views

Is it good practice to parallel relay contacts for increased current capacity?

Say I have a DPDT relay, like T92S7D12-24. The contacts of this relay are rated for 30A, but there are two sets of contacts. Can I parallel the contacts to get an effective 60A relay? Further, could I ...
1
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0answers
71 views

Obtaining maximum light from IR led for distance sensing

I'm working on a project and I'm using IR LEDs and photodiodes to measure the reflected signal. At the moment the IR LEDs are always on and drawing 100mA. It works really well except for times when ...
0
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0answers
35 views

Drawing proportional current from two voltage sources?

I have two voltage sources, a microcontroller, and a motor. I want to get the current for the motor from these two voltage sources at a proportion of my choosing using the microcontroller, so for ...
0
votes
2answers
67 views

How to light a LED using photo transistors output?

I built a circuit using RPR220 photo sensor to detect the surface displacement caused on a material when external force is applied. I could see the output on a CRO even when there are minute changes ...
1
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3answers
72 views

Will running a DC motor below stall current damage it?

We have DC motors that power wheels on a car. Because of internal friction, the motors will not actually rotate until they are given 50%+ power. However, they do make some neat noises within this ...
0
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4answers
112 views

How does a potentiometer work?

A lot of places where I've read explanations about potentiometers either go into so much detail or they're so superficial that I don't understand the actual concept behind it. How would you easily ...
0
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0answers
25 views

i do not understand what current actually is? Is it stream or wave ? [duplicate]

I am taking circuit analysis but it is just theory and they do not give enough explanation to understand what current or electricity actually is
2
votes
2answers
55 views

Peak output current of a Full-Wave Bridge Peak Rectifier

I am attempting to design the first section of my power supply. In this case, I am going through my calculations for the Rectifier section. I am simulating my circuit with PSpice and while most of my ...
11
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3answers
1k views

Why don't AC transformers burn up

I'm marginally familiar with the way that an AC transformer works. After viewing this question: Why don't all motors burn up instantly? It got me thinking about the same thing with AC ...
2
votes
3answers
94 views

Choosing “widespread” parts

Many times I know the parameters of a part to choose and find hundreds of them, but I don't know which ones I would have to order, which ones I am likely to found in a local electronic parts store, ...
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0answers
63 views

High current SMPS transformer

I would like to have some tips concerning DIY winding of SMPS transformers. Let's consider the following example (for reference only): Input: rectified 230V AC (mean value: 310V DC on the DC-link ...
2
votes
1answer
84 views

Current Transformer giving a reading when not clamped around a wire

A split core current transformers is currently clamped around a live wire. One end of the transformer's output wires are connected to the analog pin of an Arduino and the other end has a 2.5V bias ...
0
votes
2answers
59 views

Basic question regarding power consumption of different devices

I have current values for devices measured at different DC voltages. 4.2mA at 2.4V 68.8uA at 3.0V 44mA at 2.0V 65mA at 3.4V If I were to power them at a voltage of 3.6V and would like to ...
0
votes
1answer
53 views

How multimeters measure current in this circuit? [duplicate]

simulate this circuit – Schematic created using CircuitLab In the circuit shown if current is flowing from negative side of battery to positive side how multimeter can know the existence ...
0
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2answers
65 views

Will this relay handle my current and voltage requirements?

I have this relay: SONGLE SRA-24vdc-cl I want to use it to run 240V 11A device. I can see in the datasheet it can be up to 20A (section 7, line 4-5), but the relay is so small and its legs so ...
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6answers
1k views

Over 10,000 amps?

Is it possible to have a 5 meter wire that has 10,000 amps or more current flowing? I assume this can be done with a step-down transformer and the voltage could be 2V and lower... I assume that most ...
0
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2answers
70 views

How to sink current to drive 7-segment LED using a 4026 chip?

Am referring to this project here; http://electronicsclub.info/p_random.htm with a schematic like so; Key points: Resistors are not required for the LEDs because the 4026 IC limits the current to ...
16
votes
3answers
2k views

Why don't all motors burn up instantly?

A motor rated for 3S (11.1 V) has an internal resistance of 0.12 ohm. The maximum current is 22 A. 11.1 V / 0.12 ohm = 92.5 A Doesn't this mean ...
2
votes
2answers
94 views

Why are some terminal blocks blue and grey in color

Looking at some terminal blocks like the one below, why are the top level positions color coded blue while the middle ones are in grey? I understand yellow-green are for ground connections. I am ...
1
vote
4answers
207 views

Highly accurate constant current source

I want a continuous and highly stable light from an LED for around a couple of hours, for which I need a highly constant and highly stable current source. I prefer an opamp-based circuit for the same. ...
0
votes
2answers
44 views

Is the LT8500 a current source or sink on its PWM outputs?

I am using the LT8500 as an LED driver and I need to know if the leds are current sink or source. Also if I need to have resistors in serial with the PWM outputs since the output voltage is 4V. I've ...
0
votes
1answer
83 views

How to calculate maximum allowable signal swing at the collector?

How to calculate maximum allowable signal swing at the collector? How does change in beta value change the swing at both ends?
1
vote
1answer
50 views

How is the formula for the base current value derived in a three-phase per-unit system?

When analysing a power system using the per-unit system for a three phase system, why is \$S_b = \sqrt{3}*V_b*I_b\$, where as shown in the link, \$S_b\$ is the base power value, \$V_b\$ is the base ...
1
vote
1answer
64 views

What is the current before arriving a resistor and after leaving it in the wire?

Suppose we have a very simple circuit, with just a resistor between a wire connected to a power source. What's the actual value of current travelling the wire before and after the resistor? Is it ...
1
vote
2answers
65 views

Current spikes in simple transformer?

I'm using 220v -> 48v 830 W transformer directly connected to the 220v grid and used to operate my PCB drill. The issue with transformer is that it's making irregular (with 0.1-2 min interval) sudden ...
1
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0answers
35 views

What should I use: Hall effect sensor or current transformer?

I have to design a generalised kit for online condition monitoring of induction motor (1Hp, 3hp and 5hp) and monitor voltage, current and temperature. I was thinking to use a Hall effect sensor/clamp ...
0
votes
2answers
63 views

Understanding Current Draw [duplicate]

I have a DC- adapter which gives me the output of 12V and 3.3A, I want to connect it to a device which requires 12V and a few hundred milli amps, would this damage the device? or any device would ...
1
vote
1answer
37 views

Interfacing GPIO pins between a uC and RS-485 tranceiver

uC: EM357 datasheet RS-485 IC: sp3078e datasheet Two input pins on the sp3078e need to go high at the same time when I'm sending bytes. I'm using a single output pin on the EM357 to drive both of ...
1
vote
3answers
74 views

Determining maximum current through 18 gauge wire in robot arm

For a robotics application, I'd like to power some external electronics and sensors off the logic circuit in a robot arm. The components are a computer (19V, 65W => 5A), 2 cameras (1.2A), 1 light ...
2
votes
2answers
73 views

In-Flight LiPo Charging via Solar Cells

I am attempting to use thin, flexible solar panels to charge a battery on a plane (RC) for a school project. After fully charged, I will begin flying the plane, and the panels will hopefully extend ...
0
votes
5answers
105 views

Open and Short Circuit questions

I am confused on the terms Open, Short, and Closed when talking about circuits.. As far as I know: a) Open circuit means the wires are cut off so there will be no current will flow. But there is ...
2
votes
1answer
65 views

H-Bridge freewheeling current

I'm building an H-Bridge to drive some motors I have around. I'd like to have a bridge that can be powered by different power sources, for example batteries or atx power supplies interchangeably. ...