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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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191 views

Using LEDs in an output of a power supply with a voltage divider

First time posting here; it is also my first time making a power supply as a group project (been in charge for the schematic). I've already learned about transformers, rectifiers, filters, and ...
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0answers
20 views

Which power supply choose for lineal actuators?

I have two actuators each of them with the following characteristics: 16 inch, 12v, load 750 N, travel speed 10mm / s, duty cycle 25% BUT Current Draw is not specified, and I have no access to the ...
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37 views

X Ray Transformer with Full Wave Rectifier Design

I current am in possession of a center tapped X-ray transformer that can supply 80 kV and 10 mA. However, I need this transformer to supply approximately 0 to -37 kV DC at around 8 mA. In order to ...
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2answers
51 views

How to add 0.2V per Ampère that device draws? (Voltage drop compensation)

I have noticed that many mobile phone chargers already do this: For each 1 A of current that the mobile phone draws, the charger's output will be increased by 0.05V or 0.1V or something similar, to ...
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4answers
250 views

Why are these traces shaped in such way?

Please look at this image(see the PCB traces within the circles). This circuit belongs to a laptop adaptor. What are those parallel soldered-traces on the PCB traces? Why aren't they soldered to ...
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1answer
64 views

What are these soldered/un-soldered dotted-shapes? on the traces which don't have soldermask?

Please look at this image(see the soldered/un-soldered dotted-shapes which are identified by arrows). This circuit belongs to a laptop adaptor. What are these soldered/un-soldered dotted-shapes? As ...
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1answer
15 views

Soldering back the disconnected wires from the charger board [on hold]

The attached link images are the front and back photo of the board inside my charger. This charger is used to charger my son's toy car. Unfortunately, the wire soldered on this chip got disconnected. ...
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3answers
361 views

Can I combine 3x 1000ma power supplies (wall warts) to get a 3amp supply [answer: no]

I have a device that requires 3A, 9V. I also have three 1A power supplies (wall warts). Can I cut the wires of these power supplies, reconnect them all together in parallel, and use them all as a ...
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1answer
66 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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0answers
52 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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2answers
43 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
1k 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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72 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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3answers
1k views

SIM800L restart automatically

I know there is a similar question but it did not solve my doubts, I will be clear and concise. I recently bought the SIM800L module and then I started to try it, at the beginning it restarted itself ...
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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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1answer
100 views

Power supply and pcb connections to ground, earth

I am planning a pcb which is powered by two switching power supplies LRS-150F-5 (230 V/AC to 5 V/DC) LRS-150F-12 (230 V/AC to 12 V/DC) . The power supplies are mounted in their own metal box and the ...
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3answers
68 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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0answers
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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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
180 views

Power supply for BTS7960

In the beginning I would just like to mention I don't have too much experience with electronics and English isn't my native language. I would like to use a BTS7960 module with Arduino data sheet. ...
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1answer
70 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
78 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
49 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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0answers
49 views

Trying to identify a battery and its controller

Attached are two images of the inside of one of those devices to extend the battery life of your phone. This one was a promotional giveaway and only had their logo on the outside. I tried searching ...
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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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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 ...
264
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5answers
342k views

Choosing power supply, how to get the voltage and current ratings?

Power supplies are available in a wide range of voltage and current ratings. If I have a device that has specific voltage and current ratings, how do those relate to the power ratings I need to ...
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1answer
210 views

Relay switching off when under load (spot welder)

I'm building a spot welder. Schematic is under this link here: It is supposed to give impulse on relay for time determined by 555. On the other side of relay, I attach on one terminal + of 12V car ...
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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
85 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
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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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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1answer
104 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
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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2answers
49 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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2answers
330 views

Running 9v battery in parallel with Power Supply

I am putting a 9v powered circuit into an electric guitar. It will be powered by a 9v power supply through a cable, and also have a backup 9v battery on board the guitar. I am wondering if I could run ...
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1answer
203 views

Unexpectedly drawing power over serial tx/rx? What to do?

I have this TTL-to-USB-serial device (supposedly from WINGONEER, who doesn't seem to have any documentation on how to use it): https://www.amazon.com/gp/product/B06XY18XLL I'm using it to hook up ...
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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
60 views

DS3231 Real Time Clock i2c 3volt battery 5V arduino

I have a doubt I hope somebody can help me I am thinking to add to my project using Arduino Mega 5V a DS3232 real time clock. I can see on data sheet some information about the MAX voltage for SCL ...
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1answer
91 views

4 wires from from power brick to 2 wire fixture

I am attempting to hook up a 12-volt water pump to an 110 outlet. I bought an AC/DC switching adapter to make the conversion. Intended on wiring a black and red wire to a black and red wire. But my ...
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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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1answer
43 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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0answers
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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0answers
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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1answer
2k views

Digital voltmeter ammeter wrong reading

Hello! I've built a small adjustable PSU with a buck converter (XL4015 module) and a cheap 10A digital voltmeter and ammeter. It worked fine for a few minutes but after that the voltmeter started ...
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2answers
31 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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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 ...