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

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-1
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0answers
29 views

Adding more current to circuit [on hold]

I have a high voltage supply (aprox. 20kV) and I would need to increase the current while keeping the voltage. Is there any way you can think of or is it impossible? Thanks.
0
votes
1answer
38 views

Spread spectrum 400 KHz

I got a 6-phase DC-DC converter. Fsw=400 kHz, synchronization by external clock(CPLD). I need a spread spectrum 400 kHz. What's the best way? All chips what I've seen before worked on MHz and above. ...
1
vote
1answer
40 views

Inverting buck-boost vs. positive buck-boost

Should I use an inverting buck-boost or a positive buck-boost topology? Input voltage range = 19-22VDC, Output voltage range = 10-56VDC, Application = LED driver The app not I have says the ...
0
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2answers
49 views

Characteristic impedance of a transmission line

characteristic impedance of a transmission line depends on frequency of transmission as can be seen by its expression. What will be the characteristic impedance of TL if my signal has two frequency ...
0
votes
1answer
39 views

Mosfet IRF7457PbF voltage drop too high

I'm using a mosfet for powering an Arduino mega 2560 on and off. The current drawn is less than 500mA with a 12V battery. I chose the IRF7457Pbs (RS 543-0888), with these features: VDSS - 20V RDS(on) ...
0
votes
1answer
25 views

How to calculate logic gates power in microwatts in Matlab?

I am designing a circuit in Matlab2014 Simulink using logic gates and I am giving Pulse and Constant at the input of the circuit but I cannot measure current and voltage at the output of the circuit. ...
1
vote
1answer
39 views

Wireless transmission power for multiple receivers

I have just started learning about wireless systems and for some reason I'm hung up on what I feel is a fundamental idea. Consider some transmitter-receiver pair with isotropic antennas. The receiver ...
3
votes
1answer
76 views

Choice of heating element (power resistor)

Basically I need heating element which can heat up small volume of air (lets say shoes box size) up to about 60 C degrees. I am going to use 25 V source supply with 2 A current. What I thought about ...
1
vote
2answers
73 views

Best way to power a 3.3V circuit from 3.3V-to-5.0V source

I'm working on an add-on board that needs 3.3V power (~500mA) and should take power from its host board. The host can operate at 3.3V or 5V and I'd like to avoid using jumpers that would require the ...
0
votes
2answers
74 views

Transformer core maximum power

so i am an EE undergrad, and i am wondering if and how exactly does a transformer core limit its power capacity. From my understanding, the rated power of a transformer is due to the current carrying ...
0
votes
0answers
18 views

Rigol command to find if channel is enabled and max voltage/current can be applied

Hi I'm using RIGOL 832A in lab I just want to know if there's any command which returns answer 1. If channel is enabled? 2. Max voltage that can be applied to channel 3. Max current that can be ...
0
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0answers
44 views

Cheapest 120 volt offline power supply [closed]

I'm working on a project which requires 120 V to 3.3 V, 300 mA power supply. I was just going to do the standard transformer,rectifier bridge, 7805 design, like I would have done 20 years ago, but ...
1
vote
1answer
59 views

Capacitive touch on off power switch

Is is possible to use capacitive touch as a power switch for an embedded project? Can a microcontroller turn itself off and somehow still monitor an input pin? Or is there a dedicated IC that can ...
0
votes
1answer
43 views

Mechanical Power (Application) and Electrical Power (Stepper Motor) Discrepancy

For my application I need a torque of \$\tau=0.87 \, Nm \$ and a speed of \$ w=140 \, RPM \approx 14.65 \, rad/s \$. This gives me a mechanical power \$ P_m=12.75 \, W\$. $$ P_m=\tau w $$ I have ...
0
votes
1answer
48 views

High power power regulators - thyristor regulator?

I am currently working on a system design that intends to control heating in different zones. All zones in total is calculated to use approx 340kW (230V). This will be divided into 11-12 smaller ...
0
votes
0answers
45 views

Protect the USB supply

How can i protect the USB power line from external power line connections? what's happening when i connect 5V line from external power supply (such switching reg) together with 5V USB power line? I ...
0
votes
1answer
46 views

Wanting to build an automotive grade solid state relay center [closed]

I am wanting to build a solid state relay and fuse center for motorcycle applications. It will be used to drive the positive side of all components, such as fuel pump, lights, solenoids, exc. I ...
2
votes
1answer
68 views

Building a wall-wart style case

I'm working on a project that will plug directly into the wall outlet, similar to a night-light or a wall-wart power supply. Internally, I'll use a AC-DC converter like this one. It has built-in ...
0
votes
2answers
59 views

About battery capacity and regulation

For a portable application, I would be using a single 3.7V 2600mAh li-ion cell. The circuit requires 2.5V to 5V to function with the current requirement being 100mA. So obviously a voltage regulator ...
3
votes
4answers
121 views

How do you calculate the power factor of a power supply?

Is it possible to measure or calculate the power factor of a power supply without using expensive tools? If so how?
0
votes
0answers
31 views

passive filters in power quality

In power systems,how does cost of passive harmonic filters change with their rating and tuned frequency.This question is for a medium voltage distribution system.
1
vote
1answer
38 views

Modem power usage versus signal strength

Is it true that a modem (such as a 3G dongle) will use more power when signal strength is weak that when signal strength is strong? Also, can someone link me to a resource that discusses this? What is ...
0
votes
1answer
46 views

Arduino not driving RGB LED Strip

I'm using Arduino Uno with a 12V RGB Signal Amplifier and a 12V RGB LED strip. 12VDC is supplied to the amplifier. However the LED strips does not light up whether the PWN pins are set to either ...
0
votes
0answers
54 views

How long will my ~20W device last with a 18000mAh battery?

I have a Mac Mini with a max power consumption of 85W but an average power consumption of ~20W (in my experience). I'm thinking of buying a portable power source with a 18000mAh battery. How do I ...
0
votes
1answer
36 views

Minimum limit for current and maximum limit for voltage while calculating power

I have a brushless Motor then i am using in conjunction with a ESC, powered by a Lithium Polymer Battery(3S 1300mah). I just got a new Lithium Polymer battery (6S 15000mah) from a friend and am ...
0
votes
3answers
75 views

How to run electric match and microcontroller from a single power supply

We have a fairly large system that's been built up over the years for running a fireworks show from a computer (see here for the first generation software and hardware) using a pretty simple ...
0
votes
1answer
71 views

Turn Laptop Battery to a Power Bank

Is it possible to turn a laptop battery into a power bank? I have seen video tutorials and articles on how to turn AA Batteries into power banks, however, no one has created a power bank using a ...
0
votes
3answers
134 views

Using a P-channel MOSFET as an on/off switch

The project I want to build is shown below. I want to operate the P-channel mosfet on and off with variable frequency from 20-100Hz and I choose P-channel to do this so that the +350V will not be ...
0
votes
1answer
67 views

Calculating noise power spectrum

I have some signal which I have measured N different times and I want to calculate the noise power spectrum of it. Intuitively to me the way I would do this is simply calculating the power spectrum of ...
0
votes
1answer
49 views

3.3v sensor to switch water pump

I have a PIR sensor that when triggered, gives out a 3.3V signal. I'm trying to use that to switch on a 5V water pump, and I'm assuming I will use a transistor. The sensor only puts out 10mA, while ...
0
votes
1answer
76 views

Bipolar power from unipolar supply, but accounting for DC offset

I've been researching this one during the past week. I've found lots of examples of split rails, but nothing which addresses my concerns. I'm creating a new circuit board for an existing ...
1
vote
1answer
57 views

Wiring an IC for VGA switcher

Original schematic: Here is the goal switch between two VGA outputs from one source VGA input. Parts list: 1 SPDT switch for switching between A or B video outputs. 2 CBT3244AD IC chips (here's ...
0
votes
2answers
102 views

What's the frequency v power relationship of an oscillator + transmitter?

I'm starting with the assumption that a higher frequency EM wave is more energetic than a lower frequency one and thus requires more energy (and thus more power) to transmit. In my naive model of a ...
0
votes
0answers
3 views

Are there 3-pin to 2-pin power connectors for motherboards [migrated]

My (old) case front panel has a 3-pin power led connector (inc. one empty slot in the middle). My (new) motherboard has a 2-pin power led connector. How do I connect the two? If I try to connect the ...
0
votes
0answers
34 views

3 Phase WYE Heater - Wattage with and without Neutral

We use heaters with the following spec: 3500W, 277V element voltage, WYE, 480V 3phase. The heaters are designed to be connected in WYE with a center tap Neutral. QUESTION: What wattage is produced ...
3
votes
2answers
161 views

12V supply to Vin Pin on Arduino

I'm trying to understand the following section of the Arduino Uno's schematic: (Here's a link to Arduino Uno R3 complete schematic) The Arduino's site recommends that Vin should be between 7 and ...
3
votes
5answers
705 views

What causes cables to get heated up and melt in a circuit? (DC Circuit)

I know lots of current can cause heat but what else? Can too much resistance in thin cables cause heat?
8
votes
4answers
2k views

Does AC Power have Polarity?

When I run 24VAC into a full wave bridge rectifier followed by a 220uF electrolytic capacitor to turn it into ~32VDC, the source has two wires. Does it matter in what order I connect the AC wires to ...
0
votes
2answers
96 views

Bench power supply adaptation 13.8V min to 12V [closed]

I have a bench power supply, which gives a minimum of 13.8V with 20A. There is something to do for adapting this scheme to give a minimum voltage of 12V? The scheme is this one ...
0
votes
1answer
76 views

Can We send data using exisiting power outlets in homes

I am trying to build a project in which I want to transfer data through existing power outlets in a home through power lines while simultaneously using those outlets for power supply also. My question ...
1
vote
1answer
53 views

High Voltage negative power supply from positive supplies?

How can I combine two identical 5KV 15 ma power supplies that each are set up to deliver 5kv+ with negative being ground, so that they will deliver TWO -5kv outputs (cathode) and the + (anode) being ...
1
vote
2answers
101 views

MOSFET source to drain Current

Since similar kind of questions being asked before it.. They doesn't clarify how one can use it in circuit. I'm aware that a MOSFET is a bidirectional device and in one direction current can flow ...
1
vote
1answer
72 views

Power supply 5V

I need some help about choosing the best on board switching power supply that has the less electrical noise and longer life time between these schematics for a 5V 200mA board... Heating is ...
1
vote
2answers
144 views

Current capacity of wires

So this question stems from a previous question. Here Where from several tables one can see that the maximum current (Imax) is proportional to \$1/R\$ where \$R\$ is the resistance. (Or that ...
0
votes
1answer
63 views

Switching power supply 220V-5V

it's a long time that I'm looking for a 220V - 5V 200mAh switching power supply and I haven't found my solution... My board uses ...
0
votes
1answer
114 views

I want to run 20A constant current and 4.2V on a load using a variable DC power supply rated same

I want to run 20A constant current and 4.2V on a load using a variable DC power supply rated as 20A, 30V. But because my power supply is a switching CC, Cv type, and it kept switching to CV at only ...
0
votes
0answers
35 views

Mounting SSR + HEATSINK

I have made a AVR based Bluetooth mains controller. The idea is to be able to control my AC using my phone. Since I would be controlling an AC, I figured I would be needing a solid state relay with ...
1
vote
0answers
74 views

What is this motherboard component that looks like a bead of solder [photo], and can it be repaired/replaced? [closed]

As you can see, the one on the top is burnt. Whenever I plug the power adapter into the wall, the component releases a puff of smoke and the adapter instantly shuts itself off. The damage to the ...
0
votes
0answers
27 views

Is a wave guide has an ability to narrow radio beam? [duplicate]

If I want narrowing radio beam width to 0.25 degrees range , can using appropriate wave guide make a sense ?
0
votes
1answer
72 views

Identifying an IC named ID2J

Recently I was working on a 5V switching power supply project and I found the best PCB for building it. But in the middle I got confused when I saw an IC with the letters ...