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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307 views

What is the purpose of feed wire and return wire in electric railway?

Looking at the following image: Image source: The Railway Technical Website On the left of the mast there are two cables, feed wire and return wire. Are they acting like a ground cable which ...
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58 views

Brick SMPS power supply issues

I'm working on a system comprised of two boards (power board, screen board) powered either via European outlet (220v 50Hz) or a LiPo battery. Power handover is achieved via an autoswitching MUX that ...
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52 views

strong noise in microphone unless usb receptacle is grounded

I installed a Banana Pro (like Raspberry Pi), plugged an usb audio stick in, and a microphone in it. I run this thing with a properly dimensioned usb power supply (tried different ones). This way, ...
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60 views

Severe Ringing when turning off bench supply

I have an HP E3610A and I've noticed a huge amount of ringing/hash when turning the supply on and off. This is my test circuit. The bench supply is set to 6V. There are 2 clip leads (about 18" long)...
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2answers
268 views

Measuring wattage to PoE device - how to hook up a multimeter inline?

I'd like to measure the amount of power drawn by a PoE client device (PD) and would like to hook up a multimeter inline to do so. However, power is supplied to the PoE device over two pairs of wires (...
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257 views

Power Supply Fuses and Varistor

I wish to build a little decent power supply for my IoT devices, would like also to implement more protection from the live 230V AC side and I decided to put a fast blow glass fuse in a nice holder, ...
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1answer
201 views

charging lithium ion battery of 3.7v

I have a device in which I have used 3.7v of the lithium-ion battery for power supply and for charging this battery, I am using a tp4056 module. when I connect a battery to tp4056, battery fully ...
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100 views

Theory of Operation for Arc Lamp

I am attempting to power an arc lamp (which I have) using a programmable power supply (which I have yet to source.) Though the lamp is rated at 1000w (37v at 27A) I would like to power it at about ...
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1answer
55 views

Buck converter discontinous mode

I am operating the buck converter with STmicroelectronics VIPER01 IC to step down the input voltage of 200 volts to 6 volts in continous current mode 300 mA load current. The operating frequency is ...
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1answer
62 views

Identify 4 pin DC power supply connector

Can you please identify this 4 pin DC power supply connector:
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1answer
152 views

How to design for electrical connection for a food dryer

I am on this project in building food dryer to dry 2 kg fish cracker maximum per use. Based on the calculation, I only need to use power of approximately 60 watt for the heating to achieve the energy ...
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1answer
59 views

12VAC Common Reference

Working on a design where power supply (on the PCB) is 12VAC to full wave rectifier to 5VDC linear regulator. Customer switch box is also power via same 12VAC source and will be switching that 12VAC ...
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1answer
43 views

How to manage solar panel as backup power source

I have a 12V PC cooling fan (Evercool PWR-1225H12B) that will run on a 12V regulated supply. Said supply is on a 12 hour daily timer. In addition to the timed supply, I want to have a solar panel as a ...
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116 views

aluminum anodizing power supply schmetic

It has been a long time since I played with the electrons. In my day filament transformers were common and power supply design included the number and type of tubes being used.LOL Anyway I need to ...
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36 views

How to monitor device's AC current profile?

I have a specific question at the bottom of this post, but a little background is needed. I recently got a new medical device (a CPAP machine). Its power supply looks very similar to a typical ...
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102 views

Possibility of hybrid forward-flyback topology

Within the context of isolated converters, the flyback topology is nice in its simplicity as can be the forward topology, in spite of needing a second primary reset winding. However, both make poor ...
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279 views

Earth leakage from isolated power supply

I have recently put together a DIY bench power supply using a DPS5015 from Rui Deng and an old laptop power supply. Everything seems to be working fine except for a small amount of current leaking to ...
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1answer
310 views

Average current mode control compensation

This is the structure of average current mode control (source here). Please look at signal \$V_{com}\$ at the positive input of PWM modulator. For proper operation, in steady state the magnitude of ...
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55 views

Using a PC PSU instead of a dedicated professional “brick”?

Usually when choosing a PSU for a scientific instrument going into production I will go to one of the major distributors and buy something like this, which is rather expensive but well specified. ...
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195 views

How much maximum electricity bill (units) can be generated on 2 KW connection?

I have got a bill of approx 14000 Units (50000 INR) for a month on 2kW connection. As per my analysis and understanding, it can't be more than 2 * 24 HRs * 30 Days = 1440. I think electricity meter ...
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3answers
1k views

TP4056 Shutdown Problem

Anyone know why the TP4056 shuts down in this config? If I bypass it, everything works and the measured current does not exceed the limit of the TP4056.
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217 views

Power supply schematic - Question about LM358 setup

I have been working on an Arduino DC programmable power supply using: MPC4725 (Digital to Analog Converter) LM358 (Operational Amplifiers) IRFZ44N (Mosfet) Wanting to add a current limiter feature, ...
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197 views

LTC4417 Power path converter not working

I am fairly new to pcb design and I am having trouble understanding why my PCB is not working. I am using a LTC4417 power path converter and a IRF7324 power mosfet to turn on an embedded system with a ...
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1answer
1k views

Calculating AC Input Power

I'm making an AC to DC power supply that connects to mains. There's an AC to DC converter, buck converter and a smoothing LDO that outputs a DC controlled with pots. I'm verifying the supply, and ...
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134 views

DC Power Schematic Feedback (Review)

Below is the schematic of the DC power circuit of a project I'm working on. I'd like to get some feedback on whether I should make any changes/improvements. The input is from a switching wall-wart ...
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60 views

Photocoupler to Latch Microcontroller Power Supply

I'm revising my custom arduino circuit which involves powering an atmega328p. I am using a 9V battery connected to a BS170 MOSFET. Without any voltage applied to the gate of my BS170, the battery is ...
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136 views

Ripple filter @ 2 amp without breaking the bank?

I'm trying to create a +160v and +/- 100v supply that with idle at 2A. The problem I'm having is I can't find capacitors that can handle the ripple currents for the prefilter. I need to order like $...
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35 views

Grounding Class I device

I'm designing a IEC Class I device with requirement of grounding the chassis. The device use a AC power supply with V- and V+ outputs. How should I connect the ground of the internal circuit? Should ...
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724 views

Emitter-base voltage in ideal-diode circuit for voltages >5V

I stumbled over the circuit in the related question which accroding to the explanation and my understanding implements a comparator by means of two PNP transistors to pull the gate of the P-channels ...
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595 views

Potential difference between DC floating power supply and earth ground

I have a question about a simple DC floating power supply: it is as simple as possible, secondary coil -> bridge rectifier -> filter cap, as shown on the figure below. If I connect the input of the ...
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290 views

PWM Dimming Causes Flickering

I designed a 24V PWM dimmer. Basically, it drives a 24V-LED-strip with low-side switching using a MOSFET driven by a 1-kHz-PWM having 1-100% duty-cycle. There are no problems when the circuit is ...
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1answer
125 views

Driving Lights with Audio Amplifier

I'm working on a project where I want to have christmas lights (or LED strips if needed) react to music. In this case, the end goal is to have them pulse to the beats/bass of the music. There's a lot ...
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538 views

Is this a suitable common mode choke?

I've got a system here where I get 12V DC from a laptop charger which is connected to the wall. That 12V gets stepped down to 5V using the TPS56221 buck converter (running this at 500 kHz, with an ...
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133 views

Power supply unit with two negative and positive outputs

So I am trying to add a power supply unit, which takes one input and supposed to provide one output: IN: 85-265V AC OUT:12V DC; 25A (max output power 300W) However, when I look at it, it clearly ...
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666 views

HF arc starter and full bridge IGBT driver protection

Had developed HF arc starter scheme and it worked fine until I accidentally pressed arc start push button when circuit was shorted (torch stick on work peace). After that all 4 IGBTs in my inverter ...
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41 views

Mulimeter Ripple Current Error

I have two multimeters. One is very good, the other one is quite cheap. I am measuring a regulated power supply to see if it is in indeed regulated. Both so 5.4 V, unloaded and loaded. This seems to ...
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1answer
171 views

Base Drive Circuit

I've been experimenting on Half Bridge converter and there is something that I can not understand. What is the purpose of the diodes and capacitor (red one in the picture) in base drive circuit. I ...
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141 views

How to interpret LTspice simulation outputs for improving dual channel boost converter design using LTC3788

I am working on a boost converter design using the LTC3788. I would like to take advantage of the dual output capabilities of this chip to produce 24 VDC at 4 amps on one output and 48 VDC at 2 amps ...
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116 views

Transistor parrallel to Voltage Regulator

I'm encounter following schematic in a product. It gets 110VAC and provide 5V DC to the board. After many inspection I still can't understand what Q2 and R4 do in this design. First of all after T1, ...
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1answer
199 views

Supercap backup power - delayed power on

I'm trying to figure out how to make a backup power that will allow my SBCs to safely power down in case of power outage. What I thought to use are supercaps (2 in series for 5.5V) that will first ...
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1answer
114 views

Where to connect shield in USB power supply for Arduino?

I'm making a 5 volt portable regulated power supply (using LM7805 regulator IC) for Arduino UNO. I'm planning to use a USB connector as its output socket, this way I can just plug and power the ...
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1answer
57 views

Power supply higher voltage on startup

I've got a power supply that is suposed to provide 5V of DC voltage, I use it for powering an LED Strip (WS2812B) and I've measured the voltage right after turning it on and it's about 7V (for no more ...
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1answer
66 views

Switching between two power supplies to power bluetooth board

I have a Bluetooth board in which I wan to have the option to power it by a battery or power it by a wall adapter. The power input is a 5mm x2.1 mm plug with two wires (positive and negative). I have ...
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64 views

How can I evaluate on-chip bypass-capacitor's capacity based on the topology?

The transmitter I designed has been showing lots of jitter.I think there's something wrong with the layout topology.Pad of the power supply is a little far away from the circuits by connection through ...
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576 views

Power supply of board based on tp4056 with protection gives too low voltage

I have a project on small pocket board with a Li-Ion battery so I made a pcb with power section based on a tp4056 board (with protection), with LP2985IM5X-3.3 stabilizer. TP4056 charges the Li-ion and ...
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2answers
609 views

Excessive noise in amplifier circuit when switching from DC power supply to AC-DC adapter

I'm working on breadboarding this amplifier circuit before transferring to a perf board. When we power it from an adjustable DC power supply set to 12V, the audio output sounds clear. When we switch ...
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155 views

5VDC 4mA to 5V 200mA

Arduino gives a PWM output of 5V dc 4mA, the requirement of my project is 5V 200mA. how do I boost current from 4mA to 200mA by keeping voltage as 5V as the signal is a digital signal?
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60 views

How to choose a 3A power supply for a project involving a micro controller?

I am designing a project where a ATMega 328p chip triggers a 3V step up transformer to produce a 7kV spark gap. I have found some 3A transistors which I can use as obviously the 238p cannot supply a ...
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621 views

Powering a servo from a 5v, 3.3 amp power supply

I am building a Mearm robot using an Arduino to control it. The kit came with 4 servos which are rated at 5v. The Arduino doesn't output enough power to power all 4 servos so it suggests buying an ...
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182 views

UCC28C44 flyback start-up problem

I have a problem with a design of a flyback converter for a power supply. I am using UCC28C44 PWM IC. Converter should star up with at least 200V and VDD should be charged to 14V when 15V should ...