# Questions tagged [electrical]

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### Can we use 125VAC 20A switch in place of 12VDC 20A switch?

Can we use 125VAC 20A switch in place of 12VDC 20A switch? I have searched my local market and found 125VAC 20A switch. Can i use this AC switch in place of 12V 20A switch as it is not available in ...
133 views

### name of one part in electrical cables

There is an extra plastic or wrapper piece at the end of the electrical cables. I asked one of my friends about it and he said its for insulation purposes but he does not know the technical name of it....
56 views

### What are the Disadvantages of unnecessary increase in PID gains?

I read somewhere that if we increase the PID gains unnecessarily, it will cause more energy consumption of the controller and it will lead to noise and distortion in the practical. May someone please ...
2k views

### can dc voltage and ac voltage flow on same conductor at a same time?

I want to know dc and ac voltage flow on same conductor at a same time ?
136 views

### Rc filter transfer function

How do you know if a transfer function for a RC filter is correct? For example how would you tell whether or not this is a correct transfer function: $\frac{\frac{R_1}{R_1R_2}}{1+j\omega R_1C}$ Or ...
91 views

### Why AC is not used to excite synchronous machines?

In synchronous machines rotor is excited with DC and rotated so that due to change in mf falling on the conductors in stator an emf is generated.if we use Ac as an exciting means to excite rotor and ...
137 views

### Back-EMF related question

If a circular dipolar magnet is set to roll down an incline through an array of coils set out as found in a bicycle dynamo – one above and one below per set, but linearly along the incline. Arranged ...
509 views

### How to calculate electrical energy consumed?

I have a wattmeter and motor. I want to know how much this motor consuming the energy(in kWh) by measuring the power (Watt) every minute. If the wattmeter shows 500 W for 13minutes and then 0 W (it ...
616 views

### Joining high current wires

I am trying to figure out the best way to join some 12 gauge wire that will be carrying very high DC current (about 100A) for about 2 seconds. When working with lower currents, soldering seems to be ...
2k views

### Regenerative braking on an electric bicycle

I'm currently trying to build myself an electric bicycle with a regenerative braking system. I am however stuck on the regenerative breaking part. The bike will include a simple DC motor, powered by ...
349 views

### Matlab Derivative block analysis and filter design

May someone helps me regarding this!? I have a controller which will control AC motor as attached. In this controller, a stage comes where I need to use a Derivative Block before point 'B' as shown ...
363 views

### Electrical Engineer being autodidact (Without university) [closed]

for personal reasons I can't go to the university and i would like learn a lot of electronics oriented to computers, I am not new in the software programming but in all related with the hardware yes, ...
493 views

### Mathematical Modelling of AC Servomotor

i want to model an AC Servomotor where i assume that a dynamic load is attached to the shaft of AC Servomotor. the link of the paper that i have attached in the start of this post has ac servomotor ...
43 views

### Connecting a 3mm electrical wire in a non air environment?

Is it safe to connect a 3mm electrical wire (running 240 V) in a complete closed no air environment (Completely sealed "Hazard proof" cabinet) ? I will use similar to the below
45 views

### House 240 backup power to junction box from 120 inverter?

Main power outage happens frequently at my cabin in the woods. I want to power LOW WATTAGE to both legs of the panel from a single 1500W inverter. NO 240 will be attempted, but does anyone see a ...
213 views

### VA rating of Wall receptacle

What does VA rating of a wall receptacle means ? Just started using Revit for Electrical Design (120V/208V) and came across wall receptacle rated as 180 VA. Just trying to wrap my head around that ...
394 views

### Immersion water heater in a metal cup

I am creating a non-profit product for charity and I have a simple electrical question. I plan to place a small single cup immersion water heater inside a stainless steel cup. But I am going to have ...
1k views

### Triac fan speed control [closed]

Are Triac based fan speed regulators harmfult to ceiling fans ? One shop guy told me that it's being replaced with capacitor based regulators now a days. But then how can the fan speed be controlled ...
457 views

### ESD flooring in electrical room

Got one for you guys. Is there any reason why I should argue against putting ESD flooring inside an electrical room with 480/277V and 208/120V panels present? I would gladly accept any NEC ...
2k views

### How to mitigate voltage spikes when turning car ON?

I need to connect some things (LEDs and other misc.) to the 12V rail in a car. I understand that this rail gets a beefy ~100V spike on ignition. I have also heard that the battery soaks this spike (...
1k views

### What is the tolerance level of SMD resistors?

As in normal ceramic and carbon film resistors we can calculate by color codes but nothing mention over the smd components so how to get it? As nothing is ideal so I believe there will be some ...
2k views

### How to distinguish between Thermistor, Varistor and disk capacitor?

How to distinguish between Thermistor, Varistor and disk capacitor they usually look the same. Is there any way to distinguish between the three? What are some ways I could do that?
157 views

### Petroleum engineer want Electrical engineer help? [closed]

I need your help since I'm not electrical engineer :( . I'm petroleum engineer and I'm building a system to do an experiment. The system consist of five cell (40 ml) and inside each cell a ball. ...
1k views

### Does current have a physical effect on wire?

Does current have an effect on the wire it moves through? I think I heard somewhere that over time small wires in CPUs can move because of the current going through them. If it is a thing what's the ...
384 views

### Why to use 50/60 Hz Frequency and Not other Higher/Lower Values? [duplicate]

At our homes and utilities, the frequency is 50/60 Hz. Why not use any other value such as 500 Hz, 200 Hz or a small value 40 Hz, 30 Hz. Previously I searched it over the StackExchange but I want to ...
294 views

### Double batteries capactior circuit

Can anyone help me solve this problem?
453 views

### Interface Submersible water pump with microcontroller using Contactor Relay

I am making a automatic water level controller for my home,I am new to Electrical Engineering and learning things. I am using a MCU to turn ON/OFF submersible water pumps using some float switch to ...
4k views

### Can't find this electrical symbol

What is the name of this device?
78 views

### Non-mechanical load suggestions for a 12VDC / 6A PSU?

I need to provide a load for the 12VDC/6A power supply. I used a small motor before, but something less mechanical (more reliable) like a light or (anything that's not mechanical) would be ideal.
205 views

### Finding Current through element that offers some resistance and only permits current in one direction

Suppose An alternating voltage e=200sin(314t) is applied to a device that show a resistance of 20 ohm and only permits the current in only one direction and entirely preventing the current the flows ...
366 views

### How to draw a GRAPHICAL REPRESENTATION FSM

And Here is the answer, can you explain me specifically? I really dont know how to draw this graphical FSM graph.
1k views

### What's the function of ground wire anyway?

I thought Ground wire in house electrical systems was used in order to discharge electrical currents to the earth. However, I've seen people saying ground wire would drive electric current to fuses, ...
306 views

### Can I use offline UPS for a PC? Will the delay affect my PC if it is running when the power goes out? [closed]

Can I use offline UPS for a PC? Will the delay affect my PC if it is running when the power goes out? im planning to set up an offline UPS at my home i need my PC running without any disruption but i ...
123 views

### Which root locus is better and why? [closed]

which root locus is better out of these two, and what is the reason?
71 views

### AC Current confusion

when an AC generator generates current it alternates, so does both terminals of ac generators has current means both are live wires ?
66 views

### How do i solve this circuit with Thevenin's?

I am not sure how to place my voltage source after i combine the 2 parallel resistors R1 and R2. Can someone please help me with this?
6k views

### Are all electrical sockets of my house in the same phase?

Most countries use AC power that is supplied to each house. This AC power is in the form of a sine wave. Suppose I have 2 electrical power sockets in two rooms that are at the opposite ends of my ...
101 views

### Mosfet Amplifier Problem

I'm currently working on a problem that wants me to obtain a gain of 500 using a mix of CG CS CD or cascode amplifiers or just a single topology. The Vout will be powering a resistive load of 50 ohms. ...
402 views

### Average Power Equation

The equation below states the following: P = G * v^2(t) W = Integral (P) over all time Paverage = W/(time period) Can someone explain the time period (1/2t)? Why is it not 1/T (T = period of ...
367 views

### Whats a N (+,N,-) terminal on battery connection to UPS?

We have a 3 phase ABB powerline series in our site, and we are installing it. In connecting external batteries to the UPS, 4 terminals are given +,N,- and PE. I understand +,- and PE, but for what "N"...
4k views

### Capacitor Bank Rating

I need to know why capacitor banks are rated in KVAr rather than Farads? Suppose I have one capacitor bank of 10kVAr which is for a rated voltage of 400V. Will this bank provide the same reactive ...
556 views

### Understanding surface and volume polarization charges

Can someone please give me an intuition of this formulae? I am unable to visualize the formulae in equation 5.26. Specific question - How does a dielectric when kept in an external electric field ...
859 views

### Assigning Current Direction in a Circuit + Resistors

I'm a computer science student and am taking a basic electrical circuits course. I'm facing many difficulties, but the one that I want to address here regarding nodal analysis and determining whether ...
7k views

### LED lights wired in Series will not light

I have a pack of simple LED lights that I planned on wiring in my boat for cabin lights. I installed and wired them all in a simple series circuit. Power supply connected to switch, switch connected ...
232 views

### How to make safe power supply? [closed]

I have a product which required 24 volt supply. I had experienced many times my product has been given more than 24 volt supply and system gone bad. Is there any way to privant the damage caused by ...
2k views

### Standard Volt and Ampere

A recent question on here asking about how to calculate the accuracy of a circuit got me thinking about calibration in general. In particular, as EEs we routinely use volts and amperes as a unit and ...
85 views

### Replacing Multimeters with Megaohmmeters

Standard Digital multimeters can measure up to the ranges of 20 Megaohms. Then why should we use Meggers at all?
425 views

### effective diameter vs overall diameter of multi-strand wire?

Is effective diameter the outer overall diameter of a 7-strand earth wire, (about 2.1 mm), or the copper-only diameter based on 7 x 1 mm strands. (2.645751 mm) ? (Refer to answer on multi-strand wire ...