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Questions tagged [power-supply]

An electronic device which supplies electrical energy to a load. Can be AC or DC input. Typically DC output.

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17 views

Parallel Transistors Current Sharing

If we have a linear power supply, which uses parallel power transistors (NPN) as series element, with emitter current sharing resistors, then which is the maximum acceptable difference of current ...
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33 views

Capacitive power supply

What is the role of the BJT and capacitor C2 in the capacitive power supply circuit shown below?
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2answers
202 views

What does this symbol on the box of power supply mean?

I always see this symbole behind electronic devices. A close-up image of the symbol: What does it mean?
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67 views

Why does this laptop adaptor have two metal shields with different thicknesses?

Yesterday, I opened my laptop adaptor to learn something. First off, faced to this kind of shielding: There are two shields that cover the circuit. A thick shield which is covered by a thin shield ...
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1answer
59 views

Is this IR LED driver circuit with a transistor OK?

I am making a custom IR array board with a custom Arduino (only ATMEGA328 and necessary components.) So please tell me will this be fine or if I need to make some changes. IR LED = 940nm, continuous ...
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42 views

Adequate Power Supply for 300 Daisy-Chained LEDs [on hold]

I have 300 LEDs (ws2812b) wired in a series. They were sold as 150 LED/5 meters and rated to power at 9W/m, so 45W/5m strip. I would need 90 Watts to power my entire 300 LED strip. I have a 3-rail ...
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3answers
66 views

Emitter OR rather than diode OR

I'm building a power supply for a product that uses a 5V regulator if external power is connected or three alkaline cells if not. I don't want to waste half a volt or more from the cells by diode ...
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3answers
24 views

Adequate Power Supply for 300 Daisy-Chained LEDs

I have 300 LEDs (WS2812B) wired in a series. They were sold as 150 LED/5 meters and rated to power at 9W/m, so 45W/5m strip. I would need 90 Watts to power my entire 300 LED strip. I have a 3-rail ...
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2answers
48 views

Motor performance

If I was to run an electric motor rated at 24V 20A at 15V 10A and at 10V 15A what would the difference in performance be? Assuming everything is rated to safely handle more than that power.
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1answer
75 views

Replacing USB power with simple power supply

I've bought a bunch of dlink wifi cameras for my home. These all come with 5V wall wart psus connecting to the camera using what appears to be a simple 2 core cable terminated in a micro USB socket. ...
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1answer
48 views

Another Power Supply question

I am trying to troubleshoot a problem with a battery charger that accepts 11-18V DC input and can output up to 24V/8A/80W. The power supply I am using is rated for 12V10A, but if I select 10A 8.4V ...
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2answers
38 views

Using a 12V battery while simultaneously charging via Heavy Duty battey charger

Very similar to a question asked and answered but using solar panels.. BUT this time I'm asking, Can I use my 135Ah deep cycle battery to power a 2000W inverter and at the same time charge my battery ...
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2answers
38 views

Backup power supply using capacitors to help esp8266 run for 3-4 seconds after power failure [on hold]

I need to make a circuit with introduction of capacitors in parallel with input supply of esp8266(3.3Vdc) to run it extra 3-4 secs after power failure, Is it possible to gain extra 3-4 secs just ...
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1answer
67 views

Combining non-isolated switch mode power supplies in parallel into a single supply

I'm trying to combine several SMPSs each having a ~350VDC output @100mA each. Background: Purchased an unused batch of small DC->DC SMPSs in good industrial quality. Unfortunately they're too weak ...
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1answer
25 views

switching two power sources

I have used the circuit below to switch between two power sources. The purpose was to have a backup power source once the other is switched off by a controller in the system. While testing the ...
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1answer
84 views

What chips can be used to design an Anti-Counterfeit /Authentication circuit? [on hold]

I am an intern within the R&D branch of a company that designs tools that must operate with low noise at extremely high external temperatures (upwards of 175C). My boss asked that I look into ...
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1answer
46 views

Peak Detector with Reset

I'm trying to make a N.Peak Detector with reset functions. I've tried various modification to the classic peak detector without any success. What I'm trying to accomplish is: Detect the negative peak ...
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1answer
51 views

DC-DC converter not simulating correctly

I am trying to design a solar charge controller to charge a 12V battery, my solar panel is made of 9 cells that are 5W and 0.5V per-cell. I would like to make a booster circuit to get the voltage up ...
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2answers
35 views

Power Supply for Arduino on breadboard (ATMEGA328PU) from a car battery

I wanna power my Arduino on breadboard (ATMega328PU) from a 12V car battery. simulate this circuit – Schematic created using CircuitLab Is this safe ? What should I add more to make it a ...
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1answer
103 views

Not getting 2.5A or 2 A DC current

simulate this circuit – Schematic created using CircuitLab I checking the output of the circuit's current by attaching multimeter(ON 10 A) in series with a load of 3 Ohms resistor. But I am ...
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2answers
74 views

Limit 540 mA CC driver to 300 mA?

I have five 10 W, 34 - 38 V, 300 mA LED COBs I'm wanting to run these in series but to reach the voltage and watt range in the driver, I can only find a 540 mA constant current dimmable driver. I want ...
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2answers
48 views

Exceeding voltage on STM32 Vbat pin

I want to power STM32F429 Vbat pin with an existing Lithium Ion battery on board. However, the maximum voltage on the discharging curve of this battery is 4.2v which is above the maximum operating ...
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1answer
42 views

5 V from power bank not constant when supply circuit

Now I'm working on my project which contains Arduino, LCD, electromagnetic lock, 6 channel 5v relay and 500V isolated converter. My project was designed to power by using a power bank. Now I use eloop ...
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14 views

+24VDC to 5v converter - does the positive make a difference? [migrated]

I have a fairly general question, but cannot seem to find an answer to confirm my thoughts. I have a garage motor door, and on the top has 4 terminals - 1 and 2 for a switch button to open and close, ...
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0answers
9 views

16-Channel 12-bit PWM/Servo Shield check if it is powered by adapter [migrated]

I'm using Adafruit 16-Channel 12-bit PWM/Servo Shield with Arduino Uno controller In setup() I have a number of default positions ...
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3answers
69 views

What current should I choose in bench top DC power supply?

Most of the time while I'm doing my university projects, I find that only voltage requirements are given for building a circuit, and how much current I should supply from a bench-top DC power supply ...
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49 views

small party without power [closed]

I am considering throwing a little party during my vacation however this will be in a place without direct access to power... My goal is to use my laptop, a pioneer dj controller and 2 krk rokit 5's ...
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0answers
68 views

Why does a motor not work after the power supply?

I have a fairly cheap breadboard power supply and a motor. Now if I touch the wires from the adaptor (the thing that plugs into the power supply to provide it with electricity) the motor works fine ...
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2answers
44 views

The pros and cons of tantalum and ceramics in AMS1117

Task: Make a reliable power supply for sensors and an RFID card reader. Specifications: Total current consumption: up to 0.7A (700 mA.) Elements supply voltage: 3.3V Input voltage: 5V Working ...
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2answers
30 views

Does ESP8266 deep sleep make sense while on the power supply?

If ESP8266 is powered via a dedicated power supply 220V AC → 3.3V DC. Is it worth it to put ESP to deep sleep in order to reduce power consumption? For example the indoor weather station, which ...
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0answers
18 views

Solar Panel (5v/500mAh) charging USB Power bank (5v/1a)

I've been trying to find information on this but haven't found an accurate answer. I have a USB Power Bank that has a max charging input of 5v/1a and a 5v/500mAh solar panel that can output up to 5-...
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1answer
54 views

schmitt trigger causes noise

I am trying to get a 74HC14 hex inverting schmitt trigger to work. First thing I did was connect it to a power supply. When I connect the Vin and Ground ports to my bench power supply (5V), some ...
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1answer
47 views

Using a Computer PSU for its 12V output for high wattage loads [closed]

I'm looking to install some LED light bars (primarily designed for use on off-road cars) as fixed outdoor lighting on my property. I see they have models that use up to 700+ watts of power (for crazy ...
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0answers
32 views

Is there a power supply dropout time rule of thumb for router modems? [closed]

This question arises because I don't want to get too lost and over engineer a solution. I do understand a UPS could be placed ahead of the circuit, but I'm wondering if a little ingenuity can be ...
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3answers
2k views

Should I twist DC power and ground wires from a power supply?

Is it beneficial to twist the red/green power/ground wires from a low-voltage (~5V), relatively low current (1 to 5 A) switching, desktop power supply? This makes my wire bundle on a desk less ...
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0answers
115 views

Free energy from spark plugs and speakers [closed]

I just saw a video where someone uses two speakers, 3 spark plugs, a coil made from insulated wire (and terrible soldering) and manages to turn a lamp on and off just by touching the speakers together....
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21 views

SMPS 5V without load, fluctuation on load TOP258PN

I am using PI Expert Online (this) to design a smps circuit for 5V, 2.5A output. I already have TOP258PN IC with me so built circuit for that. Change from schematics: I am not using choke and using ...
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2answers
82 views

High frequency reduces power on circuit

I am not expert in electronics so there must be many errors that I am not considering. I designed a simple half wave rectifier that gives signal to a LDO voltage regulator of 3V3. In the input I have ...
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3answers
58 views

DC Power Limiting Circuit

I would like to know how to build a power limiting circuit. The goal is to be able to combine two PSU's with the same voltage in parallel in order to increase the Power output. From what I've tested,...
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4answers
1k views

How can I safely determine the output voltage and current of a transformer?

So I am building a Tesla coil with my partner for a senior design project. We safely ripped out a transformer from a microwave oven. However, after a good amount of research, we were unable to find ...
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0answers
43 views

Buck/Boost converter TPS63070RNMT is not working properly

I am working on a Buck/Boost converter design which is based on Buck/Boost converter TPS63070RNMT. Below is the schematic design. All the selected components are as per the Section 9 of the datasheet. ...
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1answer
56 views

Would this switching power supply work?

I'm trying to design an integrated power supply to use in IoT projects that I'm working on, some including microcontrollers like the ESP8266 or ESP32. In previous projects I've made, power supply ...
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1answer
99 views

TP4056 doesn't work without power source connected [closed]

I have a problem with my TP4056 circuit. My goal is to (solar)power a NodeMCU V3 with the TP4056. I simply connected the output from the TP4056 to VIN and GND from the NodeMCU board The TP4056 ...
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2answers
86 views

How to obtain 360vdc from 240vac for audio use without a transformer?

I'm in the process of creating a tube guitar amplifier with an output power of ~6w (fender vibrochamp AA764) which requires the use of 360-400vdc. How could I obtain such a voltage from mains without ...
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1answer
96 views

Designing a PCB with multiple supply voltages

I'm in a process of designing a 2 layer PCB for my device. The device is a master control board, and there will be 10 daughter boards. Various peripherals and things will be connected there: I need ...
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1answer
58 views

Power supply module is being powered by the arduino [closed]

simulate this circuit – Schematic created using CircuitLab i started a project to try and pilot a 28BYJ-48 5v stepper motor with its ULN2003 board from an arduino Nano, along with some LEDs and ...
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1answer
53 views

USB Port Amperage

So I have built a Benchtop Power Supply out of an old computer power supply to power and test misc. gadgets I have created. I would like to attach 2 salvaged USB ports from a junked computer to the 5v ...
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0answers
61 views

Radio module resetting when fluorescent tube switched on/off

I have a PCB powered by an IRM-30-12 power supply (230VAC to 12VDC). On this PCB, I have a MRF24J40MD from Microchip and a Udooneo to drive it + a 5VDC regulator and the 3.3VDC of the Udooneo. After ...
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2answers
41 views

Active Discharge Options

More and more frequently I am faced with a specification that requires the ability to discharge an output capacitance to a safe level X, in time Y. The circuit I am currently working on is 2000uF @ ...
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2answers
60 views

Understanding DALI power supply

I am working on a DALI system and I came across this schematic for the DALI power supply in a Microchip app note AN1465: It says the power line can be 12-20 Volts but the current has to be limited to ...