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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Re purpose printer power supply

I'm having few 24v printer power supplies salvaged from broken printers. Power supply has three pin power output socket. Blue,White,Blue wires are attached to it. I need to use this power supply for ...
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Effect of doubling clock frequency on computer performance

If we double the clock frequency of a CPU, does that translate to a doubling of the CPU performance? Assuming that the number of instructions and CPI are constant, we have an inverse relationship ...
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Does anybody know what this symbol means on my Samsung travel adapter?

The charger was bought in Austria two years ago, I know about all symbols/labels except this one. Google reverse image search did not help.
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voltage coparator

I have a circuit where I have to read High and Low logic level through micro-controller. Condition: when input voltage is above 15v, it should be HIGH logic(2v to 5v). List item when input voltage ...
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So i've been trying to repair my mom tv tube, but idk the problem is

So i have check the setting on the timer tv, and i disable it but, it does keep turning off every 15 - 20 minutes and if i turn it on again the times it goes off come shorten and shorten. Is it ...
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Voltage doubler - common ground for MOSFET?

I have a transformer putting out 24VAC, which I then rectify to drive some solenoids using mosfets. Some of my solenoids need higher voltage though, so I've constructed a voltage doubler: However, I'...
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HP 1740 monitor stay on 2-3 seconds, turn off and repeat

I have an HP 1740 monitor that, when I turn it on, just remains 2-3 seconds to display and turns off completely (even the pilot). It seems to me that the problem is not in the backlight. I opened the ...
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230VAC to 30VDC/6A power supply

I am working on a lab bench power supply capable of 30V at 5A. It is a linear PSU so therefore i will need 30VDC to feed into a regulator (5x LT3080 in parallel). I think that 1A is enough for the ...
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Hobbyist needs Help!

I have the following transformer: Hammond 266S6 Dual 117Vac primaries (BLK-WHT and BRN-ORG) and Dual 3.15Vac secondaries (Red-BLU and GRY-YEL). I would like to be able to create a switchable output of ...
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39 views

Old monitor’s internal power supply works only when heated from the outside…fixable?

I have this old LG Flatron w1934s that worked fine until it‘s power indicator led started flashing, and after a long while the monitor turned then on, if I heated the monitor’s back with something ...
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25 views

Getting AC potential in PCB GND

I'm using IRM-30-12 for power supply for my PCB. This SMPS doesn't have an earthing connection pin as it has Class 2 isolation protection.There is an AC potential is generated at the circuit GND which ...
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Led converter and strip [closed]

I have a Led strip and a converter (waterproof) and I want to use a dimmer key, is this possible?
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Switching Battery to Usb

I am designing an hardware including MCU's, camera , RF components etc. Shematic looks fine and my question is actually about powering part. I have put some battery powered applications based LDO. It ...
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42 views

Capacitor choice for full discharge [closed]

I'm looking for deep cycle capacitor. It will be fully charged and discharged with 1 Hz frequency. I intend to use discharge current of 300mA and charge current around 100mA. Capacitance is around ...
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57 views

Identify this 19.5V DC power supply connector

Can anyone identify this HP DC power supply connector? It's not the usual 5.5mmx2.xmm barrel connector.
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Why the body of a gas truck is grounded? [closed]

So there is a gas station near my place that was on fire. I asked one of the workers after this incident about the cause of fire and it appeared something was not right with grounding. Does anyone ...
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6answers
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Feedback diode question

In the following circuit the explanation of D1 says: “D1 connected across the input to output terminals is for protection and prevents the regulator from being reverse biased when the input supply ...
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3answers
42 views

Controlling cardreader numpad input with microcontroller

I am trying to automatically input a pin code into an electronic card reader so I can automate the process. First thought was to build a small robot finger and control that to input the code, ...
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2answers
66 views

Power IC with a resistor

I've got an IC that requires 3.3V Vdd and 550uA. My supply is at 5V. I'm reading all over the internet that powering it via a voltage divider is not advised and I should get a voltage regulator/...
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30 views

RGB LED Resistor Value and Source Voltage

I am using a Common Anode RGB LED in my project(datasheet is given below) and the different specifications for each LEDs are giving me headache. In my schematics, as shown below, I have used ...
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Line Filter in Power Supply question

I have faulty power supply in my digital reverb unit and after replacing all capacitors the problem is still there - fast on/off switching with clicking sound. It does turn on sometimes though but ...
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46 views

Selective wireless power transfer

It is possibile to power on a single led (in a led panel) using wireless powering? I know the possibility to transfer power by wireless, but, is there a way to transfer power with high precision (1mm) ...
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1answer
86 views

Amplify slow changing dc signal

A slow-changing DC signal goes from 0-30mV and I need to shift it to 700mV-900mV. I cannot use op-amps and need a transistor-based solution. Please suggest.
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2answers
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Voltage spikes on Arduino Input affecting digital and analog readings

I am working on an Arduino project where I have a few inputs both analog and digital into the Arduino from remote buttons and sensors. I have installed a prototype in our building, but when other ...
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Aim TTi EL302RT PSU : understanding the specs, and comparing

I'm considering to dump some $ on a desk power supply for myself. I'm looking Aim TTI EL302RT, with data sheet here: EL302RT Few questions I have: Are all the 3 channels isolated, have their own ...
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93 views

Is It Posible To Have Step Up Power Supply Without a Transformer?

I am trying to design a high voltage low current power supply. My purpose is to design it without a transformer. For example circuit like this : My input is 220V AC after this circuit I am going to ...
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DC to LIPO charging module reverse Feedback

I want to be able to use DC 12v to power my circuit but also have ability to have it powered by a battery. The thought I have is: * A on/off switch allows battery output to be switched on/off while ...
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2answers
51 views

How does “delta”-like three phase power source avoid short circuit? [duplicate]

A delta-like 3-phase power source is as below: simulate this circuit – Schematic created using CircuitLab This diagram is equivalent to "Fundamental of Electric Circuits, 5 Edition" Figure 12....
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38 views

Convert Power Supply to 12V + 5V from Chassis Hot-Plug Power Supply [closed]

I'm trying to build a custom server chassis for an IoT testbed. We are gutting a Dell R710 PowerEdge chassis for the devices would prefer to use the existing power supply for logistical reasons. It ...
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li-ion battery protection circuit [closed]

My goal: To operate a cellphone using a bench power supply in place of the cellphone's Li-ion battery. To this end, I removed the battery from the phone and de-soldered the anode and cathode posts ...
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34 views

Capacitors bridging over transformer in insulated power supply

I need an isolated power supply for powering a device that’s very sensitive to current leak (see below). I bought one such isolated power supply from Aliexpress. What surprised me is that there seem ...
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57 views

Positive-negative voltage from dual supply

I'm trying to build a low cost hifi (Hiraga Le Monstre) but I have two old computer PSUs at hand so I tried to use it as power source. The Monstre needs +12V and -12V, computer PSUs have both, but the ...
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36 views

Converting a circuit/ schematic onto a breadboard? electronics basics [closed]

I need to produce a complete breadboard for my coursework but due to missing school (leg injury) I don't understand how to convert my circuit/schematic into a breadboard after trying to look online I'...
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38 views

Thermal Resistance of PSU's heat sinks

I have a non functional PC power supply unit, and I would like to keep its heat sinks, but they have no model or part number in them. Is there a way to estimate, calculate or measure their thermal ...
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63 views

Raspberry Pi UPS circuit review request + improvements

Based on this question I created the following circuit: Since I made some (component) changes, first I would like to have a validation of the circuit for long-term usage (and some improvements). ...
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61 views

Leakage inductance is function of the air gap

I would like to know why leakage inductance is function of the air gap transformer. How does it influence the leakage flux ? What is the relation between them ? Thank you very much :)
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Is building a DC-DC PSU PWM controller from discrete components a terrible idea?

I am building a 1kW PSU that is controlled with DSP MCU. It requires a lot of features such as synchronous rectification, bidirectionality, current regulation. Those features make the PSU very exotic ...
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57 views

How the electric water heater and stove works? [closed]

I notice that some appliances have heating elements such as electric stove and water heater. I know that both of them using heating elements maybe some type of a resistor or something. I want to know ...
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Defining power supply current specification

Let's say I'm designing a power supply with input 120-600VAC and output 48V/100mA DC. The load for the 48V output is: A 3.3V switching regulator Two LEDS (~2 mA each one) An ultra low power ...
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Power supply filtering RCL-filter vs alternatives (for LF-RFID driver)

simulate this circuit – Schematic created using CircuitLab This schematic is the manufacturers dev-board design for the RFID-IC power Supply, using a large power inductor at 4A I_RMS and 22uH. ...
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43 views

Suggestion on Power supply design

I am looking for Transformerless power supply design. I have MCU 5V. and would like to drive 12V/24V relay with single LED. i have 4 pots 10K/200k for timing So i prefer 230VAC to 12V/24Vdc output ...
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Is there a simple circuit that can change the AC output voltage from a transformer or AC-AC power supply?

I have a device that requires 9V AC and rated for 2.1 amperes. I thought I could modify the output of either of the following voltage supplies to meet those values: A power transformer that outputs ...
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98 views

Linear regulator heats up at 60 volts

MY goal is to design a regulator which could receive (12 V to 60 volts DC as an input) and 5 volt with 60 to 70 mA current as an output. The reason I used three BJT's NPN (Q1, Q2, Q3), so I thought I ...
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Can I still use this power supply if I clean off the rust from the transformer?

I have power supply for a vintage Timex Sinclair. The unit was sealed but the cable felt loose so I pried it open to inspect the connections. There was a knot on the other side so it was just the ...
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Power supply output voltage drift with temperature

The PSU that I've built, output voltage is drifting when it's turned off; First set values: Turned it back on again after 10 hours: The values being read using a 16 bit ADC and is spot on. The ...
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25 views

ts461 op-amp: Vcc and Vdd in datasheet

I thought to use the op-amp TS461 in an audio circuit as a signal amplifier. Here is the datasheet. In the datasheet, for power supply, the pins are Vcc and Vdd. Due to my newbie-ness, I was expecting ...
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51 views

How long will a 32v 15A (500Wh) e-bike battery last outputting at 5V 1A?

I hope it's okay to ask this here My e-bike has a Lithium Ion battery (32 Volts, 15 Amps), and it has a USB-A output, marked as 5V and 1A, I have 3 questions: How long will this battery last while ...
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ACS712 current measurement not working

I have ACS712ELCTR-20A-T and I have connected it with the 5 Volt/10A converter. Vout in the schematic diagram above, is connected to ...
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56 views

PWM that can handle rapid on and off cycles?

I am working on a prototype project with a large electromagnetic solenoid. I want to be able to vary the strength of the solenoid via a PWM (preferred), or constant current. The issue I’m having is ...
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35 views

Max power transfer of source with variable internal resistance

I have been reading how to obtain maximum external power from a source using the maximum power transfer theorem. However, it is for a source with a finite internal resistance. Can you have power ...

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