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Questions tagged [electrical]

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23
votes
3answers
3k views

Why solder mask are not applied to RF PCBs

I've gone through some of the RF PCB designs. In which solder masking on the traces are not present. Like this one Is there a specific reason or performance issue to remove that?
19
votes
10answers
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 ...
17
votes
7answers
3k views

Staying in Phase On The Grid

I have been an EE for over forty years and never did find out the right answer to this one.... How do power-stations and transformer switching stations ensure that the power they are feeding into the ...
14
votes
3answers
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 ...
11
votes
2answers
1k views

Is it a good idea to connect a line buffer to ground?

Got a quick question. I'm dealing with 74VHC125BQ,115 and I won't be using one of the line drivers; the rest are connected to UART. So, I'm wondering what I should do with the last one. Is it a good ...
11
votes
1answer
2k views

Symbols: Double-arrow circle enclosed “10” on electronic appliances

What does the symbol that says 10 inside the double arrowed circle mean? I have seen a similar symbol on another appliance that had the number 25
10
votes
2answers
3k views

Why does the current not skip resistors R3 and R5 when R6 and R4 have no resistance?

I do not understand why the current still flows through resistors R3 and R5 when R6 and R4's resistance is 0. To me, it would seem that the current would skip R3 and R5, however the answer key says ...
9
votes
2answers
2k views

What property of a BJT transistor makes it an amplifier?

I know how we can amplify a given signal using BJT transistors by biasing them. But I would like to know what is that crux property which enables BJT transistor to act like an amplifier. Is it the ...
8
votes
2answers
273 views

Phasing Order in IEC Color Codes

Currently, IEC 60445 international standard is used for conductor terminal color identifications. I've obtained different versions of the standard (2017 being the latest) and also IEC 60446, which was ...
7
votes
8answers
861 views

Bulbs on seperate circuits triggering third bulb

I would like to know if the following is possible, and if it is possible, roughly how the wiring should be done ... I have 2 light bulbs (BULB1 and BULB2) connected to SEPERATE switches. I want to ...
6
votes
2answers
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 ...
6
votes
1answer
4k views

Can't find this electrical symbol

What is the name of this device?
5
votes
2answers
760 views

Bulding a physical calculator from scratch [duplicate]

As you can probably tell I am relatively new to the electronics scene and I'm rather stuck on a project I'm doing for school. I am on my second year of an Electrical engineering degree, tasked to do ...
5
votes
1answer
181 views

I purchased a few of these units and have no idea what they are. Is there anyone that might have some suggestions?

The item measures 1" wide and 1-1/4" high nad about 1/2" front to back
4
votes
3answers
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 ...
4
votes
1answer
617 views

Would the motor reverse if phases swapped for this case?

A servomotor power connection pins are given as follows: U V W are the three phase terminals. Would the motor reverse if I mistakenly swap phases U and V namely if I connect pin 1 to W and pin 3 to U?...
4
votes
2answers
616 views

Capacitor and inductor working principle

I want to know that there is opposition mechanism of current in inductor say back emf than what is opposition mechanism of voltage in capacitor ??? And also want to know that when inductor suddenly ...
4
votes
1answer
774 views

What is wrong with this soldering iron?

It's body is blackened, just after 5 minutes of heating and it's body is also bent. How can I solder when the iron itself works so poorly? P.S: I am using it for the first time.
4
votes
1answer
401 views

MOSFET: How can I find conduction parameter and transconductance based on graphs?

So I have my graphs (below) with various MOSFET characteristics. I don't know device dimensions or geometry, therefore I can't solve for the 2 directly with an equation. Otherwise I would just do that....
4
votes
2answers
428 views

Calculating total torque of stepper motor to lift and rotate some weight

I am going to design a system that would be control remotely. The system consist of stepper motor and solid cylinder rod of about 30 inches long and needs to lift about 0.5 lb/0.223 kg mean up to 90\$^...
3
votes
1answer
147 views

What symbol is this?

Does anyone know what this step between the two lines mean?
3
votes
5answers
182 views

Grounding conductor meant to protect electrical devices?

I had a home inspection performed on an old house recently. The inspector noticed that some of the outlets had an unconnected third prong. He told me that the absence of a grounding conductor on the ...
3
votes
1answer
183 views

Giant pogo pin or spring probe pin for registration during electrical test

Solved: if you search for "GP-2 PCB Board Umbrella Shape 5.3mm Tip Testing Probe Pins Receptacles" you will find these probes! Thanks for the help! I am designing an electrical test fixture, and I ...
3
votes
5answers
183 views

If ground and neutral are bonded at main panel, why aren't all grounded device chassis energized?

I know this is a question with variants that have been asked countless times on the internet and on this site. Believe me that I have scoured through these questions and answers in search for a ...
3
votes
1answer
92 views

Create my own battery for my electric bike [closed]

I was wondering if it's possible to avoid buying a $400 48V 15Ah battery with an output of 54.6V and 2A, and instead make one by joining multiple 3.7V 5Ah batteries in series and or in parallel? Is a ...
2
votes
4answers
1k views

Voltage Drop Calculation (AC)

Hope someone can help me out and point me the right direction to solving this. I am trying to do a voltage drop calculation to see the VD % for the cable selected. The following are the values, ...
2
votes
2answers
362 views

How do designers know about kilowatt power of wind turbine generators like 1.5 MW?

Generators and transformers are always designed in kVA because designers never know about the load it will provide power to. Then how do we know the wind turbine generator will deliver 1500 kW or 2 MW ...
2
votes
3answers
1k views

Safe use of Coiled Cable [duplicate]

So we have this machine at work, a strapping machine, and it has a long power lead which is left loose on the ground, and it's getting gradually destroyed - accident waiting to happen. I know that ...
2
votes
2answers
2k views

Where does branch circuit neutral current go in a single phase or three phase electrical panel?

Specifically, I would like to know the exact path of travel for the neutral current when it comes back from a load to the electrical panel. I am an electrician of 20 years and have recently acquired ...
2
votes
2answers
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 (...
2
votes
4answers
103 views

Generator to home wiring

I live in South Florida an as such need to have generators for hurricanes. I have 2 Generators, a small 3300 Watt Inverter and a big loud 9000 Watt generators. Edit: My plan is to use only 1 ...
2
votes
1answer
81 views

What are different battery capacity algorithms used? [closed]

I need to implement an algorithm to know the capacity of a battery. I don't want to use any external gauges which are available on the market. Can you suggest which algorithm(s) is/are popular? Can ...
2
votes
2answers
53 views

Connector type suggestions required for 12V supply

I made a power supply enclosure with a mains switch and now I need external DC connectors to be mounted in the slot shown. I want to mount two female connectors onto a 3D printed panel, that will sit ...
2
votes
1answer
93 views

Do Electronic Engineers need to be “licensed”

Do Electronic/Electrical engineers need to be licensed? I have heard something along these lines but I do not recall where. And if so what is the license name? If I take a stab at my own question I am ...
2
votes
1answer
157 views

Transformer rectifier set. A question about the schematic diagram

This is a high voltage transformer (53kV) and rectifier that is used to power an Electrostatic Precipitator. The schematic shows a jumper between terminals H1 and H2 with a label "Remove jumper for ...
2
votes
2answers
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, ...
2
votes
2answers
98 views

How current is steady after pinch off voltage?

I was studying the JFET. In the books and other material it is mentioned that when the voltage between the drain and source is increased then drain current is also increased. After a certain point (...
2
votes
1answer
74 views

Trying to wire in LED to show cooker element is on/off

Hi I'm a mechanical engineer so please bear with me. I'm trying to wire in an LED to show whether a cooker element is on or off. Looking at the diagrams below, the easiest way to do this would be to ...
2
votes
1answer
125 views

splitting sensor signal line

Is it possible in circuit design to split like say a temperature sensor line reading into 2 wires, and read by 2 different system/circuitry? My motive is to tap the signal line in a safe way without ...
2
votes
1answer
68 views

How would you design an electromagnet for maximum force when you have a fixed power available?

There are number of variables like current, wire dia, number of turns, dia and length of electromagnet. The distance at which force is applied is constant The distance is nearly 12 inches. Power is ...
2
votes
0answers
63 views

What is the off-white powdery material found at the base of GU5.3 light bulbs?

I've noticed most GU5.3 light bulbs, both halogen and LED, contain a granular material at the base. There seems to be considerable variation in how much of this powder is present, even within the ...
2
votes
0answers
50 views

Get position along electric wire [closed]

Do you know the game called Buzzwire where the aim is to guide the grip mounted loop through the wire maze without touching the loop against the metal maze all the way to the end? is it possible to ...
2
votes
0answers
29 views

Switchgear dielectric testing and impulse polarity

What is difference between negative and positive polarity impulse test? Why Negative only done for internal dielectric strength and positive polarity impulse only for external dielectric strength? ...
2
votes
0answers
121 views

Please help identify this vintage component [closed]

I got this item in a bidding lot and have been trying to figure out what it is ever since. The nearest I can tell it is either an electro shock therapy device or perhaps a remote detonator. It has ...
2
votes
0answers
103 views

Identify this circuit symbol with two overlapping circles [duplicate]

I came across some images of schematics and have never seen this component before - what is it?
2
votes
1answer
170 views

Why does a turbine with PMSG and full converter system draws reactive power when turbine is stopped or there is no wind?

Our turbine has a permanent magnet synchronous generator and full converter system (rectifier diods for rectification and IGBTs for chopping dc link voltage and as inverters) which means its generator ...
2
votes
1answer
219 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 ...
1
vote
6answers
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 ...
1
vote
3answers
246 views

Dependent voltage/current sources

I'm so sorry for that questions, but we need to understand what's going on behind the concept/theoretical of using device "dependent voltage/current source"! My question: Yes, we are using dependent ...
1
vote
3answers
156 views

How to figure out what resistors are in the E12 and E24 series?

Is there a way, other then remembering, to figure out what resistors are in both of these series?