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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34 views

Power supply charging backup power - current flow via mosfet

I have following diagram on falstad Top +5V is main PSU (12V 10A). Bottom +5V is battery (12V 2.3Ah). I have load about 2-3A so I dont think diode is good solution. Well I am trying to achieve ...
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1answer
71 views

What is (was) this component at ZD102 (top left, next to powered serial connector)

Part at ZD102 is overloaded with too much current and blown. It's three legged, with two legs on the south side and 1 on the top. The left side (white in the picture) is blown and has since ...
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54 views

12VDC Switching to 17VDC high amerage

It's been years since my undergrad work as an EE. I am a physicist and medical researcher now, but, as a startup, we all take on anything we can. Let's face it... 12VDC high current PSU's are cheap. ...
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34 views

Changing between usb power and battery power using P-Channel MOSFETs and a CMOS Invertor

I am trying to switch between USB power and a single cell lipo using two mosfets. Would the circuit below be ideal or is there a more efficient/reliable way to do this? When the USB is connected the ...
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46 views

Multiple source power supply

I am trying to design a micro-controller power supply that can use three power sources with a particular order of priority. The sources are: 5V USB - overrides all other sources when available 12V DC ...
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8 views

How to use the earthing connectors on an NVR-Switch-PoE Camera system? What power outlet to use?

Location: West Bengal, India. Electrical Supply: 220v AC. I am setting up a network camera system for home surveillance. All installations will be done by trained electricians and integrators. I ...
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1answer
123 views

Arduino PSU with battery backup (SLA) and mains/battery monitoring

Please could somebody review my following schematic, as it is my first attempt at a PSU circuit. The aim of this circuit is as follows: I am using a 15V (150W) PSU to power an Arduino, 2 separate 12V ...
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33 views

Low Power Supercapacitor LTE modem supply

I am interested in your comments about the following LTE modem power supply from a single 3.6V ER34165 battery with minimal Iq (quiescent current). The battery can only handle 200mA continuous ...
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3answers
35 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
76 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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72 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
102 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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82 views

Can an inductor lose its characteristics permanently after short saturation?

I was testing a SMPS (boost) where I had an overcurrent due to overload for a few seconds. The inductor saturation current is 2A. Although I could not measure the current, I am quite sure that the ...
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133 views

3.3V LDO Selection

If you've ever tried to find an appropriate LDO for your project you may have noticed the incredibly vast range available on the market. During my searches, I discovered this particular regulator ...
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1answer
83 views

Hybrid power supply output voltage

I have a question. I want to make 30V/4A hybrid power supply with stepdown regulator LM22679 as an preregulator and LM338 as an linear regulator to smooth voltage. LM22679 would be powered by Mean-...
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94 views

How does this negative voltage generator work?

I managed to fry a piece of moderately rare equipment due to connecting it to the wrong voltage power supply, and I'm now trying to diagnose what's wrong. Luckily, reverse engineered schematics are ...
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2answers
117 views

How do I connect an LED with floating DC voltage?

I want to connected an LED at the output of 500V DC. This DC power supply is made by 3phase DC rectifier and is floating. I would like to have a display on the front panel of the supply which will ...
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53 views

1V Overshoot and Undershoot on Power Rails of LTE Module

I have designed a PCB (four layer) having SIM7600I LTE Module. The Stackup is: Signal & Component Layer with Ground Pour Internal Ground Power Plane Internal ...
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153 views

Op Amp-based CV LM317 power supply

As many others before, I'm aiming to build my own simple CC CV lab bench PSU based on the LM317 regulator. Now, I've defined most of the circuitry, but I'm stuck with a particular design choice ...
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62 views

What are these programming terminals for a 2 kW power supply?

Does anyone recognize the programming terminals on the real panel of this power supply? I would like to get the 50 amps out. It is an ATE1 made by Redfern radio, it is an old army surplus. Going in ...
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1answer
44 views

Off-grid solar system

I'm doing a project on designing an off-grid PV system to power a constant load at 900W at 12V, 24/day. If I choose PV systems that are rated at 48 V or any other voltage will that mean that any ...
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1answer
53 views

PIR Sensor for bulb in room

This has been very long since I left electronics but recently I restarted taking interest in it as hobby. I bought some PIR sensors from Aliexpress and found it is very simple to implement if I have ...
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56 views

Cant recognise a Damaged component of switched-mode power supply

I was repairing an smps ATX power supply I found a damaged component that I could not it recognise. I thought it's a power switch since it was mounted to a heat sink along with tow D13007 NPN power ...
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1answer
160 views

What to consider when powering multiple devices in parallel?

Briefly about my background, which might inform the question. I'm currently self-educating myself on some electrical engineering on-the-job. I'm learning from Art of Electronics and some other ...
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0answers
22 views

Which power converter topology has higher benefit of EMI/EMC?

Which power converter topology can be best suited for EMC compliance for small power converter to be used in LED lighting products. In my context I'm using a 5W non-isolated AC-DC converter which is ...
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2answers
148 views

Battery failing. Oscilloscope?

The question is - is there an inexpensive oscilloscope I can use to measure DC voltage and current to see why my battery pack is failing to power a DSLR? In order to take long time lapse photos with ...
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1answer
54 views

Is Power Factor only relevant at rated load in Light Equipment?

As you might know, LED lamps over 25W require a minimum 0.9 power factor in Europe. I have designed a PSU for a specific LED lamp which is rated about 50W. There is a PFC-stage (crm) in order to ...
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1answer
65 views

Heating issues with solar charging circuit

I am using the above circuit to charge a 7.4V Li-ion Battery.With input MPPT voltage set at 12V, I have applied 13V input voltage to the circuit. The battery is charging at 1.4A. (according to the ...
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100 views

2 Switch Forward Converter Volt-Sec/Charge Balance

I am attempting to design a 2 switch forward converter. I understand how to do the volt-sec balance and charge balance when the converter is as shown in the ideal 2 switch forward converter below. I ...
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46 views

Voltage drop on power bench supply for channel being off

If I measure voltage drop between terminals of my bench power supply (spec) I get -15 mV when channel output is turned off. Why it is not reading 0? I believe it's due to internal impedance of the ...
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81 views

Routing the main power supply across a PCB and choosing vias for it

I have a board that uses several different switching converters with 33uH ferrite beads that take up a fair amount of space. I'd originally intended to keep them all at the top of the board (not top ...
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1answer
176 views

SMPS Flyback transformer selection

I am trying to design a SMPS for a project (I have to make a custom one for integration purpose). This SMPS have universal input (85-265V AC at 50 or 60 Hz) and an output of ideally 53V (but it can ...
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32 views

Can I connect 2 power supplies for 16 meters LED RGB strip?

I've bought 2 sets of 10 meter LED RGB strip (7.2w/m) for a room. Then I've cut them to around 8 meters each to get 16 meters. Everything seemed fine but one thing, because it's 2 separate controllers,...
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52 views

What factors should I consider when choosing a high amperage power supply?

I've searched around, but I haven't found an answer to this particular question yet. I'm building an elecromechanical project which requires somewhere around 60 Amps at 12 Volts. While this may not ...
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27 views

Designing a CCM Boost PFC rectifier circuit

I am working on designing a CCM Boost PFC rectifier circuit, supplying up to 2.8kW at 400Vdc nominal, while taking 230Vac, 50Hz controlled via negative feedback in the average current control mode. I ...
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121 views

Designing a +10 V -10 V +7 V DC power supply for audio equipment

I've recently purchased a tape recorder (Tascam Midistudio 644) that was very cheap because the previous owner had lost the power supply. The PS-M1 power supply that originally came with this unit is ...
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1answer
101 views

Ringing issue on I2C FM+ bus between MCU and few sensors - Power supply issue?

I'm experiencing some issues while probing a problematic I2C bus on the oscilloscope. We want to interface several TLV493D-A1B6, with a STM32L4 (we are working as well on STM32F4 and have the same ...
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1answer
63 views

Dual channel linear power supply

As a learning project, I'm trying to create a simple linear power supply using LM317. The basic circuit is well documented on internet, but I want to create a variant that allows me to have multiple ...
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44 views

XBOX 360 PSU for walkie-talkie chargers

I'm in the process of modifying a 360 power supply to power a 6 unit Motorola radio charger. I've got the +12v and the ground wired to live and ground on an NL-2 connector; and I've jumped the blue ...
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55 views

LEDs driven by GameBoy sound

My circuit does not work as I thought it should and I'm really confused now. What I want? Two LEDs which will pulse to audio LEFT and RIGHT channel separately. And same for display BACKLIGHT, but ...
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78 views

Linear power supply and mains filtering and protection

I'm designing my first linear power supply for my project which needs dual rail 12V (the regulation from 15V to 12V is on another board, 7812 and 7912). The +12V (+15V) rail will draw about 250mA, the ...
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1answer
74 views

Power Supply Pumping

A similar question has been asked, but I wanted to get to a more fundamental understanding of when, in general, power supply pumping occurs in a class D amplifier. In general terms "power supply ...
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29 views

supply-voltage supervision circuit (follow up)

I am trying to build a supply-voltage supervision circuit based on the design suggested in 2nd answer here (What is the simplest way to turn off some circuit when supply voltage reaches a minimum ...
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78 views

Capacitive discharge excess being used for battery recharging

I am currently designing a circuit similar to a cattle prod that is intended to be attached to a drone. The cattle prod is powered by a lithium-ion battery, charging up a capacitor and then quickly ...
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131 views

Use of 3 phase transformers which are ∆-Y connected and Y-∆ connected

Different literatures say different things regarding ∆-Y and Y-∆ 3 phase transformer connection... Some say that ∆-Y is used for step down and Y-∆ is used for step up while others say just the ...
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196 views

switching between two similar power sources - solar battery and cr2032

I'm trying to create a circuit powered by two alternative power sources. The first one is a Li-Po battery charged by a solar panel and the second one - standard 3v battery, ie. CR2032. The circuit ...
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48 views

DC DC converter opamp compensation

I have simple doubt. I am making a closed loop DC DC converter flyback, I am using opamp for compensation. It should be a single input single output network. Input voltage is 24-32 volt, output is 5V ,...
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1answer
60 views

Variable LDO implementation - capacitor size

I am designing two linear power supplies that will: Drop 9V DC to 5V DC to power a Raspberry Pi around 2.5A Drop 9V DC to 7.5V DC to power a DAC under 3A I plan to use Texas Instruments LDO UCC283-...
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62 views

Why are 65W and 90W common amongst laptop power supplies?

I have seen Dell 130W, Lenovo 120W, some 230W or 210W gaming laptops, etc. . These are different numbers. But I have seen both 65W and 90W power supplies from Lenovo (65W 20V 3,25A with rounded DC ...
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124 views

Control variable external power supply with Arduino

I'm currently working on an air pollution controller project and I have a problem to control an external power supply to supply 5V, 1.5V or 0V to an MQ7 gas sensor. Using the direct PWM output to ...