Where power is a primary concern for the design under discussion. Use the "low-power" tag when that applies.

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0
votes
3answers
112 views

What is the purpose of MOSFETs in this schematic?

On the main power line there are two MOSFETs but for what reason? The MOSFETs in question are Q1 and Q2.
0
votes
5answers
119 views

Does wire diameter affect the electricity bill?

Does thickness of wire affect the electricity bill, for same load? Thicker Wire has lower resistive losses ,does this reduce power bill? Does a longer length of the same diameter wire increase bill by ...
-3
votes
0answers
24 views

multiple circuits off [on hold]

Came home from work and found multiple circuits(2-30a, 2-20a,1-15a) not working. Went to power panel and found 30 amp breaker tripped. Reset all breakers in box but power remained off to the 5 ...
0
votes
2answers
44 views

3 power supplies in parallel

I have 3 power supplies all of which are stack-able. Powermax PM3-100 2 x SUPERNIGHT 12V 30A Do they have to be identical to stack? I can adjust the voltage but would like to get 160amps if ...
0
votes
1answer
55 views

Does 230v three phase have a high leg

I have an old printing press that needs to be looked up. The nameplates on the equipment say 230 V three-phase . The building I am putting it in has 120 - 240 with a Delta high leg. I am worried that ...
1
vote
3answers
99 views

Is this a power resistor?

I'm trying to repair an electrophysiology amplifier (AXOPATCH 200A). It has this power resistor which I desoldered because I suspected it was broken. The color code (red, green, black, gold) gives 25 ...
0
votes
2answers
73 views

Square wave at line frequency. How does it work?

I found the following circuit next to a switching power supply in an electrophysiology amplifier (AXOPATCH 200A, an instrument for a technique called "patch clamp"). References to power outlet: ...
0
votes
2answers
60 views

What is the most efficient way to prevent reverse polarity to an opAmp?

Above is a part of a circuit which is a Schmitt trigger. As you see 24V DC Vcc and Gnd are the power rails. I will set up this circuit and some other people are going to hook up input output and ...
0
votes
0answers
33 views

Why did I need to switch several appliances in order to power my electric stove? [migrated]

This is a bit more theoretical but I am confused as to how this may have happened. I own an electric stove that is plugged into one of those large 240V sockets on the wall. Yesterday when I switched ...
2
votes
2answers
62 views

External power to STM32F4 Discovery board

I've recently finished programming the STM32F429ZI DISC1 board. I'm fairly new to this and now want to move away from connecting it to the PC via USB and power it up via a power supply. At present I ...
-2
votes
1answer
48 views

power supply input : AC 13V output : DC 5v, DC 9v,AC 8v

i am alredy to develop a schematic of power supply with Trasnfo 13V , 1,5A : so this my schematic and i want to voltage in U2 be continue and i need a solution and i am chagin now the schematic ...
1
vote
1answer
54 views

How to calculate energy transfer in inductive heating?

I designed an inductance heater. Its inductor is calculated 50 uH as below: And I draw 9.4 A AC current at 33 Khz of it. But, I want to know how to calculate the transferred energy to the ...
0
votes
1answer
57 views

What Type Of Switch Is only on for a second [duplicate]

I am looking for what type of switch is only only for a split second (1 second max) even when held. Basically: Press and hold button-->LED only on for a split second and back off even though I am ...
0
votes
0answers
37 views

HVDC Bus Arcing

i had a arcing and a explosion inside my vfd. I cant tell why it happened and we assumed may be its because of a loose nut which tied the inverter input terminals to the DC bus from converter, And ...
0
votes
2answers
82 views

Are SMT components bad for high voltage applications?

Majority of the assembly factories are asking for SMT jobs. My gut tells me through hole would be a better option for a high voltage application. Before the high voltage project is started, we need ...
-3
votes
0answers
26 views

How to design a circuit for a mini inverter for power backup of output 12v-0.5A [on hold]

I want to design a mini inverter with 12v-0.5A output for power backup,please tell me the details and give the circuit diagram.
0
votes
0answers
21 views

Parallax servos (from BOE) move when no commands are sent through Arduino

I have Arduino zero and I'm using two continous parallax servos for movement. I have 2x5AA batteries, 5 for arduino and 5 for servos (1.5V each battery). In code I only use servo.attach(pin) nothing ...
3
votes
4answers
107 views

How do power stations maintain 50 hertz?

In the UK our mains standard is 230v AC at 50 hertz. So I understand that the generators at the power stations need to spin at exactly 3000rpm. This is true no matter what source is (nuclear, coal, ...
-2
votes
1answer
59 views

How much power could a 5 x 3 cm turbine and a 5 x 5cm solar panel generate? [on hold]

I would like to make a project and generate a few power using a combination of a small wind wheel (let´s say 5 x 3 cm wheel) and a small 5 x 5 solar panel. I am not sure what the median wind speed is ...
0
votes
1answer
46 views

buck converter, no load start

I've been working with a buck converter since a few weeks, I've tested it with load and it works just fine, but today I've measured the output with no load and saw some unexpected behavior. ...
1
vote
4answers
50 views

Simple soft start for high power mains device

I have seen, but cannot find again, a really simple implementation of a mains soft start circuit. The thing I'm thinking of involves a power resister inline of the mains. When the device is started, ...
3
votes
3answers
135 views

Powering a microcontroller inductively from mains wire

I am in the process of making a mains power monitor using a SCT-013-000 CT clamp and an arduino mini, running on batteries. Even though I should be able to get many months of operation from two small ...
-1
votes
1answer
17 views

STATCOM connected at PCC with Wind energy system, source and non linear load [closed]

If Statcom injects reactive power at PCC and the PF is improved. How can one say that active and reactive power is exchanged? If Statcom injects reactive power what happens to active power?
-3
votes
0answers
59 views

Possible to shut off power using magnetic fields? [closed]

I've been considering a theoretical scenario similar to Ocean's Eleven, where they used an EMP to kill power to a city to get into a casino. Considering the effect that a magnetic field has on the ...
0
votes
3answers
76 views

Switch mode PSU minimum load

Alright, I know I am going to get a lot of flak for this, but let me reassure you that I have already spent the last few days reading on Google while going back and forth from the bench to test ...
-2
votes
1answer
63 views

Is there supposed to be a voltage differential between V- and Earth Ground on my Power Supply? [closed]

I'm debugging something in my machine that's causing it to blow my communication chips (AtMEGA16U2 for USB connection) when I noticed a voltage differential of 0.3VDC-0.9VDC between V- and GND on the ...
0
votes
0answers
79 views

MOSFET circuit: Calculating power in a resistor

This is the problem and the second question. I know by default Power = VI, but I'm not sure which voltage to take (I'm assuming Vds). I know Vgs controls Vds. I assume the Power here is Vds x Id, ...
-1
votes
0answers
48 views

I'm building a prototype and need to power 2 12 volt motors [closed]

I'm building a prototype and need to power 2 12 volt motors. Given the power source will be hidden within the prototype Im looking to use 4 18650 batteries in series. One - Will this work? Two - how ...
0
votes
0answers
27 views

Switching power supply [duplicate]

I am currently working on a project of electronic being powered by DC power (7-40V) from car. The device is supposed to run properly (with several load of total 3-4A at 3.3V) when the car is turned on ...
1
vote
0answers
55 views

Using a fruit or salt-water battery to power a motor

I´m trying to build a fruit or saltwater battery to power a motor. From my 8 cell saltwater battery connected in series, I get a reading of 5V or so and 2-3A... but it won´t fire up my 5V DC motor. ...
26
votes
6answers
5k views

How do electricians know where the line is down?

I had a power outage and I thought about the utility poles near the street. How do electricians know which power line is down considering that there are many miles of them? For example, if there's a ...
-1
votes
1answer
32 views

What is the transmitted power (dBm) of a mobile phone when 4G connection is enabled? [closed]

Is it unhealthy to leave the 4G connection on all the time? When talking on the phone, should one turn off 4G because the phone is just next to the head?
1
vote
3answers
85 views

Power draw from 120V AC Outlet

According the the following link, a minimum of 4800W is drawn from an electric stove when all burners are turned on: http://www.ehow.com/how-does_5179441_many-watts-electric-stove-use_.html. I'm just ...
0
votes
0answers
18 views

Measure the reactive power in a three phase system

In a recent lecture at university an assistant explained that in order to measure the reactive power in a non-symetric three phase system we should connect three wattmeters in the way shown in the ...
3
votes
7answers
370 views
+50

Role of Electrolytic Capacitors and whether they can be replaced by Film capacitors in battery operated power converters

In battery operated power converters such as motor controller ( half bridge or full bridge ) bulk capacitance is placed across Vdd and Gnd . I thought this was unnecessary since the input is DC and ...
4
votes
4answers
598 views

How do reactive currents cause power transfer?

I read in 'The Art of Electronics': Power factor is a serious matter in large-scale electrical power distribution, because reactive currents don't result in useful power being delivered to the ...
0
votes
2answers
95 views

Why does my Kill-a-Watt read Power of only half the Voltage times Current?

My Kill-a-Watt is displaying that its output is 120 V, 0.16 A, and 10 W. I'm confused... I thought P = V × I from basic EE. Why do I see only half the expected value here? (This is a USB charger, ...
0
votes
2answers
86 views

How to drive power MOSFET by logic level signal without inverting phase?

I struggle yet another day with very simple problem (circuit). This challenge seems to be very common, but nowhere I can find a complete solution: I have a heavy load (12v / 1 Ohm peltier = 12A max) ...
-1
votes
1answer
43 views

what kind of type resistor do I need in PTH05050W? [closed]

I found what I need to apply my xilinx virtex5 FPGA board, PTH05050W 6-A, 5-V INPUT NON-ISOLATED WIDE OUTPUT ADJUST POWER MODULE at www.ti.com. Maybe, this need to change by resistor to set output ...
0
votes
2answers
92 views

How to change logic when system shuts down

I try to think on a good way to control motor when I shut down the main PCB (which includes the MCU). How the system works today is when it's ON, the MCU enables the motor, the motor moves a ...
-2
votes
3answers
74 views

What does the signal from an NFC pulse look like?

When a smartphone comes into close proximity with a passive NFC tag for example, what does the power pulse from the smartphone 'look' like? i.e what is the magnitude of power that is supplied, what is ...
1
vote
5answers
116 views

Difference between current and power

I am a bit confused about the difference between current and power. I am hoping someone can explain the difference to me maybe using an analogy or something. I do understand that current at a point ...
0
votes
1answer
31 views

Power Management Unit: How to consider limit to connect electronic component to power rail

I am a bit confused about the way to dimension Power Management Unit, and power rail for electronic system. I understand quite well LDO and DC-DC in terms of voltage, but i don't understand well ...
0
votes
3answers
77 views

(Capacity 20hr: 65AH) Does this mean 65amps per hour for up to 20 hours?

Cranking Amps: 675 Im trying to find a good battery for a project. That part where it says "20hr" keeps making me rethink what i sorta hope it means.
0
votes
1answer
32 views

I want to supply under 1.1V to xilinx virtex5 Vccint how to make the volatage? [closed]

I'd like to supply under 1.1v to xilinx Virtex5 Vccint. The input voltage is 5. But I can't find any reference how to make like under 1.1v. Does anyone know how to make it, please give to me any ...
0
votes
3answers
38 views

DC Bus Conditioners in VFD Drives

In VFD Drives, DC Bus conditoners are used to protect the DC link supply from transients. Can you please let me know the different scenarios DC Bus of a VF Drive gets these transients and their ...
0
votes
3answers
74 views

How to get a LDO voltage under 1.1V with lm1117 adj LDO?

I'd like to get voltage under 1.1v with lm1117-adj in 5v input. The problem is that I don't know, is this possible to get what I want the voltage under 1.1v? update This is what I've got exactly ...
2
votes
2answers
42 views

Feeding a load with very low impedance

I need to provide a reasonable amount of power (40-50W) for a heat pillow, how should I design the power supply circuit if the load (Enamel Insulated Resistance Heating Wire) is 2,5 ohm. I can't ...
0
votes
1answer
54 views

What drawbacks to bucking, then boosting the same current?

Are there any real negative drawbacks - outside of the double drop of efficiency - of DC-DC boosting a power line that was already DC-DC bucked? I'm building a modular system, serially linked through ...
2
votes
1answer
60 views

Finding the resistance of a practical inductor having its reactive power

Suppose I have a simple practical inductor as such: simulate this circuit – Schematic created using CircuitLab L is known. R is unknown and we need to find it. The supply frequency (say ...