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Voltage, otherwise known as electrical potential difference (denoted ∆V and measured in volts) is the difference in electric potential between two points (adapted from Wikipedia). Voltage can be constant (DC) or varying (AC).

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1answer
82 views

why do the electronic transformers that i remove from circuit boards keep exploding when connected to a 230v main [on hold]

for the past 3 months I have removed several transformers from PCBs to try and use it for a different purpose ,but as I connect it to a 230v main supply they just keep exploding . I don't think my ...
4
votes
10answers
1k views

Best approach to step down 220VAC to 160VAC?

Hey Electrical Engineers, I'm a newbie to electrical engineering (I am a software developer by trade and am starting to work with Raspberry Pis and want to learn about basic circuit design). My ...
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0answers
50 views

Creating a complete picture of induced current flowing [migrated]

just a copy of https://physics.stackexchange.com/q/422286/203741, maybe I'll get answers there I'm on the way to understand em waves, but I decided, that I need to completely understand a current ...
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votes
0answers
25 views

Replace wall adapter with different voltage and different ampere [duplicate]

I have a cellphone wall adapter which its output rated at 5V/4.5A output, is it safe to replace it with another adapter that rated at 5V/1.6A? It charges the phone for like 15 mins and i feel hot when ...
0
votes
4answers
114 views

I want to draw 20 amps from my home power outlet is there any way to do that safely?

I'm wanting connect up a bunch of Raspberry Pis (micro computers) to one power outlet in my home. At about .5 amps per computer * 40 computer means I will need to draw 20 amps. Now, I know that I'...
0
votes
6answers
114 views

Why can't high current substitute low voltage [duplicate]

I know this look stupid, but why high current can't substitute low voltage. I read many articles about the difference between the two, and asked my professors, but still have some doubts and blind ...
1
vote
4answers
155 views

Why do we care about voltage and current not power only

I don't understand why do we care about voltage and current supplied to any components, why not just the power, no matter how much are the current and voltage? For example: a red LED needs 2V to ...
0
votes
2answers
89 views

Voltage doesn't add up in LED circuit

The circuit consists of following: simulate this circuit – Schematic created using CircuitLab And video on this link. Summary: When there is no current flow on the circuit, supply voltage is ...
0
votes
1answer
72 views

12V motor or 24V motor for go-cart? [on hold]

I am making a PVC electric go-cart. I want to know which is better: a 12V motor or a 24V motor? I want good speed and good torque, because I don't want it to struggle with my weight (I weigh around ...
0
votes
6answers
102 views

Why doesn't voltage drop across this resistor when transistor is off?

The following excerpt from a book explains the functioning of the circuit below: When V_in < V_th (device threshold voltage), the supply voltage (V_dd) is measured at the outlet. When V_in is ...
0
votes
3answers
59 views

How does the voltage drop to negative values at t = 0 when the voltage starts with 0 V?

I understand that the voltage in the inductor is 0V because it behaves as a wire with a constant dc source while the switch is closed. But why does it drop to a negative value when the time t = 0 and ...
4
votes
4answers
1k views

Creating required voltage across a device using basic electrical principles [duplicate]

Let me explain what I mean by an imaginary case. Let's imagine a 10 V battery in series with two resistors equal in resistance value. The voltage in between those resistors is 5V according to the ...
0
votes
2answers
50 views

Over-voltage on a current regulator

Let's say I have a current regulator, or a LED driver, set at 4V that can sink 20mA. If I connect a white LED rated 20mA at 4V to it, then everything is fine. But what happens if I replace, in the ...
0
votes
0answers
57 views

Protection of DIY car camera circuit

DESCRIPTION I have no background in electronics. As my primary reference I'm using "Practical Electronics for Inventors" (PEFI) 4th Ed., by Scherz and Monk (2016). I plan to get my basic electronic ...
1
vote
1answer
43 views

Building a High Voltage Rectifier with a continuous negative output

simulate this circuit – Schematic created using CircuitLab In the past, I have worked with high voltage projects, but seldom with HV rectifiers. Thus, I was curious how I could build a ...
0
votes
5answers
187 views

Electrical apliances overheating when receiving LESS voltage

I've been wondering for a while now, why do some electrical appliances overheat and burn out when you lower their incoming voltage? Shouldn't the less voltage mean they receive less current, and less ...
0
votes
1answer
62 views

High current dual power supply

I've been trying to build a dual power supply with an output of +/- 12V 3A, I have based on the circuit of a basic power supply using LM317 and LM337, but these components are limited to only 1-1.5A ...
0
votes
1answer
39 views

+-10v variable power supply

I need to generate a variable voltage ranging from +10v to -10v in order to control a motor driver. What are ways to generate this voltage? To clarify: the motor driver takes +-10V as an input. +10V ...
0
votes
0answers
44 views

Testing voltage regulator with load

Hi I want to test an MP1584EN voltage regulator. I supplied 12V and I want to turn to 4V The specs say that I can't use that without load (I don't want to use the real load because I don't want to ...
2
votes
1answer
257 views

Why does my board start smoking when I put in a higher battery same voltage?

I just got my custom PCB in the post from PCBWAY. Plugged in small battery I got with adafruit only 2000mah at 3.7V (PKCELL LP803860) and showed the LED light to show it was being powered so I ...
0
votes
2answers
60 views

Can Micro-controller bear the voltage at its pins more than its rated voltage?

I have a micro-controller, for which i have a datasheet specifying the ac/dc characteristics of that mcu. But in this datasheet there are no absolute maximum ratings only the operating conditions are ...
1
vote
1answer
42 views

Trying to calculate Vae by Kirchhoff KCL

I have this circuit. I am trying to calculate the voltage between A and E by using Kirchhoff current law. This is what I did. First I wrote the equation for the left side, starting at A clockwise: ...
1
vote
2answers
53 views

400V to 230V ADPAK 4000

I've recently bought a packaging machine second hand as I currently have a new business which I am running from home and I'm hoping this machine will help with products I need to package. The issue I ...
1
vote
0answers
52 views

Voltage drops after connecting two batteries in parallel

I have two batteries 12V GEL 130Ah, each charged to 14.4V. After connecting them together in parallel, the voltage drops gradually and equalizes at 12.99V. (I use 10mm^2 short cables to connect them ...
2
votes
3answers
491 views

Single supply from dual supply?

I've got a power supply delivering +/-28V, referenced to a common ground. In addition, I have a device (an isolated DC-DC converter, RS3-4815D) which accepts 36-72V input voltage across its V+ and V- ...
1
vote
1answer
63 views

Basic RC Theory circuit

I had an issue using an Arduino Nano to investigate simple RC circuits. The capacitor would not fully charge to the supply voltage. I assumed it was something to do with the digital pin circuit on the ...
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votes
0answers
30 views

How do I convert the signal from a voltage transducer to a readable/usable voltage reading with an arduino? [on hold]

I'm building a datalogger with an arduino. I have a voltage transducer hooked up and feeding into the arduino but I don't know how to convert the signal into an equivalent voltage reading. I don't ...
3
votes
2answers
128 views

Is there an upper limit of voltage than can pass through a wire?

The way I understand it, electric wires heat up because there is too much current passing through them. There are tables for various materials, how much current can pass through a given cross-section ...
0
votes
2answers
89 views

Automotive circuit to power ATTINY

Trying to make a simple but reliable 15-12v to 5v circuit to power the ATTINY85 from an automobile (15v-12v), wondering if I have the right components and ratings, I don't know a lot about circuit ...
1
vote
3answers
91 views

“Capacitor” for regulating AC line voltage?

I have an issue with my air conditioner. When it clicks on, the lights in my apartment dim for half a second. If this was a car audio system, I would just wire some large caps up to the battery to ...
0
votes
3answers
174 views

What's the simplest 110ac to 5vdc circuit that can power an ESP wifi board?

I've found this esp with relay pack: The only thing missing for this board to work is the 5v dc power supply. Normally a 110vac-5vdc power supply will have some filtering and other things needed to ...
0
votes
0answers
69 views

making op amp output == V+ rail

so I'm building a linear power supply and I've faced a problem, that is the maximum output of the op-amp is (V+)-1.5V. The (V+) rail for the op-amp is powered from a Lm317 regulator, which needs 3V ...
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votes
1answer
102 views

Is sticking a fork in an outlet safe? Considering body resistance and outlet voltage [closed]

I was reading this question: How much voltage is "dangerous"? and it seems to me that in the right conditions, connecting yourself to a live outlet is perfectly okay. I am in the United ...
1
vote
3answers
86 views

How to find out which end of a dead battery is the anode, and its voltage [closed]

The battery pack for an old rc car I played with as a kid, has died. Salt crystals everywhere, smells like vinegar. The pack consists of 8 batteries of AA-size connected in series. The red markers ...
0
votes
2answers
85 views

How come no voltage is meassured across my electrolysis tank?

I've built myself a electrolysis tank, using a plastic barrel as the container, rebar as the sacrificial cathode, a 12v 15A car charger (DC), and a Sodium Carbonate solutions as the eletrolyte. The ...
0
votes
2answers
68 views

4-20mA loop voltage to high

I have a 0-16 bar pressure probe connected to a module called Adca UD-720. The probe works on a 4-20 mA loop and the readings are ok. This module also has a 4-20 mA output and I need to connect this ...
1
vote
1answer
36 views

Trigger Edge Detection Voltage issues

I'm trying to get an ESP8266 to wake up via external trigger. The trigger in this case is a PIR, which sends a 2+ second high signal when motion is detected. I'm using an edge detector to turn that ...
1
vote
0answers
39 views

How to get NodeMCU to detect an external switch closure of an unknown voltage?

I'm getting really into home automation as a side project of mine and one of the next things I would love to automate is my doorbell. Short question: If I have a switch (momentary button in the form ...
0
votes
0answers
42 views

2V Reference from 2 1V Shunt Regulators

I have 2 1V shunt regulators (http://www.analog.com/media/en/technical-documentation/data-sheets/ADR510.pdf). How can I combine them, if possible, to yield a 2V signal? In addition, I will be using ...
0
votes
1answer
27 views

Power consumption of LD33CV voltage regulator

Does LD33CV voltage regulator consumes any power when there is no load? I used my multimeter and it shows the current flow as 0.00A without any load. But I feel my battery is draining out because of ...
1
vote
1answer
70 views

How to connect one pin to ground when an another analog pin is triggered

I'm trying to combine two working electronics projects into one. I have a standalone piezo sensor that I can read values from when it vibrates via an arduino, and I have a standalone audio board (no ...
0
votes
0answers
73 views

What is the voltage at this point in the circuit?

In this diagram, R03 and C06 both blew. Everything else reads good. I'm trying to figure out why this circuit blew. If TR02 was connected in a EBE way by accident could this cause this? Would it still ...
2
votes
3answers
339 views

Is it safe to use this relay with mains voltage?

I'm new to electronics and have recently fallen in love with it, after buying a few NodeMCUs to play around with. I currently have a load of them around my house monitoring things like temperature and ...
-1
votes
1answer
35 views

What is the exact value of voltage at T in square wave form?

at t=0s v=1V; T=5ms v=1,0,-1? which one? looking at graph.
1
vote
1answer
85 views

Measuring 200 volts safely

While I can measure line voltage safely, I need to write a procedure to have someone else measure the voltage. The load is pure resistive,and I want to measure the voltage across it, with a battery ...
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votes
2answers
115 views

Regulating 240 VAC down to 200 VAC [closed]

I'm designing a fryer machine, and we want to sell it over the world, and trying to minimize the problem of the different voltages, so we already asked our heaters supplier to custom make our heaters ...
1
vote
2answers
97 views

Need help identifying this part please [closed]

This is on a control board from a crane...not sure of crane mfg or country of origin. Anyway, owner lost 12Vdc to the board and tried to jumper it in...ooops. This is where the smoke came out...can't ...
0
votes
1answer
34 views

Totally noob here,help me choosing the best method of powering led

First of all im sorry for the grammar because english is not my 1st language,so bear with me. So im trying to power up 100 0603 red smd led,its a generic brand and all data i could gather was its 1.8 ...
2
votes
2answers
45 views

Determining minimum safe wire width at high amps in a DC 12V system

In a 12V DC system, given a particular maximum current and length of wire, what is the best method to determine the minimum width (gauge) of that wire? In particular, what method is best for high ...
0
votes
2answers
22 views

Ideas to smooth variable AC voltages/spikes reported to ADC circuit

I’m trying to integrate a 40+ year old ac motor and remote controller with a device using modern ADC controllers to remotely manage the motor turning process. The legacy gear is an old CDE Ham-M ...