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Questions tagged [power-supply]

An electronic device that supplies electrical energy to a load. It can be AC or DC input. Typically DC output.

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Decoupling capacitors for operational amplifiers

when in the refence design of an amplifier (for example OPA856) we see the + sign in a capacitor schematic, does this necessarily means we should use electrolytic capacitors? If there is no positive ...
Andromeda's user avatar
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Is this schematic for an LED power status drawn correctly?

I have a simple schematic drawn out in KiCAD for a single purple LED to light up when there is power running through to a array of 5050 RGB LEDs. The reason I'm not sure my schematic will work is ...
happycamper1221's user avatar
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Connecting thermal Pad to the negative supply voltage

I want to use OPA856 and there is a thermal pad. In the datasheet it is mentioned that it should be connected to V-. In my configuration it is V- is -5v, but there is a very small copper region for -...
Andromeda's user avatar
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Can off-the-shelf "Ideal Diode" modules be used in Diode Or-ing circuit for power redundancy systems?

I'm designing a 12V UPS for my router and modem, and have come across common diode or-ing circuits such as this one: (source: Static and Dynamic Behavior of the MAX40200 in a Diode ORing Application) ...
QuickishFM's user avatar
1 vote
2 answers
155 views

Why are 2 diodes needed instead of 1 when diode-ORing two power supplies?

I see many circuits online of dual power supplies connected in parallel through output diodes on their outputs, to provide redundancy in case the main one fails. Usually the primary supply is an AC-DC ...
QuickishFM's user avatar
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20 views

Computer PSU Intermittent under load to PCIe Slot

So I am trying to use a computer PSU as a stand alone power supply. I have a Seasonic Focus+ 1000W gold PSU that I am trying to use to power some 12V monitors. I modded it slightly to accommodate the ...
GMoney's user avatar
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3 votes
2 answers
860 views

Tantalum capacitor for op amps

Normally for opamps supply voltages, it is suggested that there should be (100 nF + 2-10 uF) on the positive and negative supply pins. The second capacitor which is in range of uF should tantalum? Or ...
Andromeda's user avatar
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What kind of IC is this - damaged in the TQFN10 housing, marking WEA

I have a problem with HMI Allen Bradley, The ETHERNET port does not work, I found out that this area is powered by an IC in the TQFN10 housing with the code WEA. What kind of arrangement is this?
wojtiqs's user avatar
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1 answer
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Lithium-ion battery 36V, 10Ah in electrical scooter

Battery lithium 36V, 10Ah is running for 9 hours with no load on the motor (with 0.5 A draining) which gives us 4.5 Ah, and for 2 minutes with load on motor (with 17 A draining). If we consider 4.5 Ah ...
Mohamed El Khamlichi's user avatar
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2 answers
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Is it necessary to connect the (-) terminal to earth when connecting two bench top power supplies in series to achieve a bipolar supply?

I have noticed when researching online that it is always mentioned to connect the (-) terminal to earth when connecting two power supplies in series to create a bipolar supply. Is there any issue with ...
Pernel_Sned's user avatar
2 votes
1 answer
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Peak current mode control loop compensation calculations

I recently came across a rather nice straight-to-the-point application note by RickTek (AN028) on how to calculate approximately the compensation network of a PCM buck regulator. Link : https://www....
Yannick's user avatar
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3 answers
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Can I get very high current (1000s of amps) using multi stage op amps?

If I wanted to build a power supply that could output 1000s of amps at low adjustable voltages, could I do this by using multi-stage op amps? Is this the best way to build a high current adjustable ...
jlaufer's user avatar
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2 votes
0 answers
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How do I solve DC offset GND between 2 power supplies 220V to 12V/GND? [closed]

The setup: Two modular synths (lets call them A and B) with each their own power supply making 220V AC into DC +12V, GND, -12V. I measure a DC offset (like 6.5V) between the GND's of synths A+B (no ...
user3810130's user avatar
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1 answer
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Preventing spikes in inductor current (probably) caused by lab power supply

As part of a university project I'm trying to produce a current through an inductor (610uH), that'll eventually be used as a solenoid. I'm producing this using a PWM voltage produced by a TI GaN ...
Emerson SD's user avatar
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3 answers
46 views

Can an adjustable constant-current power supply drive an audio amplifier?

I have a MeanWell HLG-240h-48A power supply that was designed to drive LEDs. I would like to use it to drive a 48V DC audio amplifier, and I was wondering if that is possible or not? It has adjust ...
Michael Böckling's user avatar
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How do DC/DC converters work as lithium battery chargers, continued

I have a 96V LiFePO4 pack (32S), 206Ah, that I would like to charge. Obviously, 0.5C is a boat-load of current... I want to charge it off of household single-phase 110VAC with a 30 amp breaker. So, I ...
JAY PRABHAKAR's user avatar
-2 votes
1 answer
56 views

Atx psu yellow wire [closed]

I have an old 500 watt psu, the yellow cables on the psu box say 12 volts, but with the voltmeter I am testing, it is 6.80 volts!! Is the psu broken? Is there any solution for it? I also tested all ...
Farshid Vosoogi's user avatar
-1 votes
2 answers
73 views

how to choose the optimum discharge resistor?

I was wondering how to choose the value of the dicharging resistor in the figure below: The figure comes from : Figure link SPECIFICATIONS: I'm building a system with fast-switching transistor-based ...
Nedou's user avatar
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When/why to use a power source selection switch?

I'm designing an automotive device that will be taking power from the car's battery. It also has a USB port that will be primarily used for firmware updates and possibly datalogging down the line. I ...
Alex Jegers's user avatar
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1 answer
51 views

Can inrush current of an SMPS damage EMI filters?

I am assembling an electronic product using off-the-shelf components. I want to connect the device directly to the power socket, so I plan on using a switching power supply (this) to get the 12V ...
AjejeBrazorf's user avatar
1 vote
1 answer
73 views

Overshoot at powerline

I had a problem with a bunch of series connected electronics devices containing microcontrollers. At seemingly random times the microcontrollers in the PCBs broke. The rest of the circuit stayed ...
luukito's user avatar
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0 answers
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Can I connect 0V between 2x 24V Power supply in different devices?

Devices: Robot (24VDC 10A power source, used for an IPC, sensors, electronic boards, CAN communication, DI/DO etc) Mini automation (24VDC 10A power source but different brand, used for a mini Siemens ...
Sebastian's user avatar
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Capacitance Formula derivation

Can anyone help me with how this formula came in the first place (marked in red)? I am not able to understand the denominator term. This is with reference to Double Pulse Test taken from the book : ...
Andr7's user avatar
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3 answers
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When does the tRAMP timing begin for Cyclone 5 Power Supplies?

I am currently designing a power supply setup for a Cyclone 5 FPGA. In the datasheet, it is stated that if power supplies do not reach operating conditions within the maximum tRAMP time allowed (100ms ...
DownInFlames's user avatar
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How can we interpret Cgd in parallel with Cds in the buck circuit?

From this document, it's straightforward to see why Cds is included there because it's in parallel with the high-side switch, and its energy will be dissipated via the Ron of the switch when it's ...
hana's user avatar
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2 answers
43 views

Safely using a "switching power supply" with 220V raw wire input

This article features something called a "switching power supply", which transforms a 220V AC current from regular european power outlets to a DC power output, which can then be used to ...
Yes's user avatar
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-1 votes
2 answers
37 views

USB Power delivery: what happens if device requests intermediate of power supply's supported powers? [closed]

For example, if you connect Power adapter that supports USB PD 3.0 with PPS, output of 5V, 15V, to a device which requests 9V (and does not support PPS), is it possible that power adapter would give ...
Foldus's user avatar
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0 answers
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Wire an external dual volt ammeter display

I am trying to install a volt ammeter display to Meanwell 3000w CSP-3000 series on the load side. How would the wiring work? TIA
Randy98's user avatar
4 votes
4 answers
544 views

Inductor energy storing in buck converter

I am trying to understand inductor energy storing during ON time in buck converter. Energy stored in inductor of buck converter is (Input Power -Output Power)*Ton Lets say output power is 5 W and ...
Power Path's user avatar
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Batteries safe for use in low-pressure conditions

I want to create a device for use in skydiving. Why when there are ready-made solutions? Because I am a skydiver and an electronics hobbyist, I would like to create something myself and experiment ...
darkanzali's user avatar
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0 answers
77 views

ATmega328 experiences freezing or hangs when the ceiling fan is turned on or off

I've been working on a project, but I've hit a snag. Every time I try to turn the ceiling fan on or off, ATmega328 gets hung/freezes. Let me break down the project for you, so you know what's going on ...
mechaTronics Tech's user avatar
1 vote
0 answers
37 views

How to calculate values for current and voltage limiting resistors in variable power supply?

I have an assignment, where I have to calculate the values for a current limiting resistor (R3) and a voltage limiting resistor (R14) for a variable power supply. The input voltage to the circuit is ...
Magnus's user avatar
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2 answers
69 views

I need more current than an LM1117/NCP1117 at 5V can provide (i.e > 1A)

I've got a simple power supply circuit to power-up some old-school TTL & seven-segment display boards (legacy computer front panel stuff). My first built for the 5V supply was with an NCP1117 (i.e....
Martin J Levy's user avatar
0 votes
1 answer
58 views

Current limiting stopped working on a power supply

I have an old power supply (Tesla BS554) and all of a sudden the adjustable current limiter stopped working. The supply is designed to limit the output current up to 1 A, but I am measuring short-...
Atropin's user avatar
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0 answers
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How to Power 2 MG996R Tower Pro Servo

I tried powering a MG996R Tower Pro (180 deg metal gear) servo from an Arduino UNO and ended up hibernating the host PC. I want to power two such motors (in parallel configuration) for 10 minutes a ...
Aditya Jain's user avatar
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1 answer
41 views

Charger Output and Device Compatibility: A Safety Concern [closed]

The device we have has a 5V 1.5A input, and the charger has a 5V 2.5A, 9V 2A, and 12V 1.5A output. If we use the charger at 12V 1.5A for a while and then switch to a 5V 1.5A device, could the device ...
ABCDEFG user157844's user avatar
1 vote
1 answer
94 views

Help identifying chip in Huawei motherboard

Can you help me identify this chip? It looks like a SOT23-5 chip, it seems to be part of the USB-C Power Delivery. The laptop doesn’t power up because this chip seems to be part of the negotiation ...
L. Ricardo's user avatar
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1 answer
26 views

In a PFC boost converter, would input current distortion happen during initial voltage build up- when input is higher than output?

It is said that "Boost DC voltage output must be higher than the maximum line peak voltage otherwise you will introduce distortion (harmonics)" Shown below is the simulation output for a PFC ...
Dynamic_equilibrium's user avatar
0 votes
4 answers
89 views

Why does powering an ESP32 directly from a power supply work, but when powering through a pMOS it doesn't?

I have this circuit which is used to switch on an ESP32 from another MCU. The GPIO goes on, the nMOS circuit becomes closed and the pMOS gate voltage drops to 0 which then also closes to allow the 3V3 ...
verpas's user avatar
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0 votes
1 answer
64 views

Wide input voltage range buck/boost converter

I am designing a power supply circuit for a battery-operated device. My list of requirements: Very low quiescent current (ideally under 1 uA), where by "quiescent" operation I mean no or ...
Foo's user avatar
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0 votes
3 answers
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High-side N-MOSFET without a driver or charge pump -Still turns ON- Is there any application involved with this?

To turn on the N-channel MOSFET on the high side, a higher voltage against source terminal must be applied to its gate terminal. Usually we use an extrenal driver or charge-pump. Is there any ...
Dynamic_equilibrium's user avatar
0 votes
1 answer
120 views

Transimpedance amplifier with OPA838 - instability

I have the following circuit as a transimpedance amplifier for ultrasound application: I checked all the possible criteria for the stability of the circuit, including phase margin, step response ...
Andromeda's user avatar
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2 answers
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USB Type C mobile phone charger Design using MPQ4242-AEC1

I am planning to design a USB type C charger for my bike. This is the first time I am designing a USB charger. I decided to use MPQ4242-AEC1 from MPS. A 12 V will be coming from my battery. As per my ...
Confused's user avatar
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1 answer
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Suppress LED turn off latency due to residual charge of capacitors in the power supply

I am using a 24VDC output MeanWell LRS power supply. I convert it to 5VDC on my PCB using a buck converter. A green LED (power indicator of the system) is connected directly to the 5VDC of the PCB ...
Tommy95's user avatar
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0 answers
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Is my power supply well scaled?

EDIT Sorry that I have bother you ... I found my mistake thank to your idea @Attie it was reversed polarity ... I plugged this jack female whe I wasn't awake enough ! One picture is worth a thousand ...
Seba99's user avatar
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1 answer
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An upgrade of a simple welder

I've been needing to get some welding projects done, but am reluctant to cough up $800 or more for a TIG & stick combo welder. However, I have an old simple buzz box welder (basically an oversized ...
Tempus Nomen's user avatar
1 vote
1 answer
151 views

Should this Chinese power supply be earthed?

I recently bought a piece of equipment from China, and it came with a laptop-style power supply. I immediately opened the supply to check if it was electrically safe, because we all know how lax the ...
Sod Almighty's user avatar
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1 vote
3 answers
65 views

Can I supply two different voltages with the same boost converter?

I have a VFD matrix display that needs both 90V and 70V to power on. I already designed a boost converter that will give me the 90V. I was wondering if I can just put a voltage divider at the output ...
MXVG's user avatar
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1 answer
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What's the best way to make sure I have a known VCC on a battery powered device?

I'm making a portable device (well not really portable, but intended to be set up away from mains power) powered by AA batteries. I need a stable VCC as I have displays that I don't want the ...
Steam Ranger's user avatar
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2 answers
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SGM2052 LDO Vbias pin connection

I am using SGM2052 LDO in my design. Using its fixed voltage version.In the datasheet you can see that it has a pin called Vbias. The description of Vbias is given below. Below is the typical ...
Confused's user avatar
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