Questions tagged [power-supply]

An electronic device which supplies electrical energy to a load. Can be AC or DC input. Typically DC output.

Filter by
Sorted by
Tagged with
1 vote
0 answers
75 views

Looking to find the value of this high-power resistor

I'm trying to find and replace this resistor and I'm having a heck of a time; it seems one of the bands has faded quite a bit. I'm guessing it's the second band because of how the bands are spaced, so ...
1 vote
1 answer
52 views

Multiple AC-DC power supplies: one direct AC wall plug or two?

I'm building a data acquisition system that needs to power sensors and a high voltage contactor at 24Vdc, 12Vdc, and 5Vdc. After reading another post, it seems it is best to use separate AC-DC power ...
2 votes
4 answers
312 views

Why does the L298N schematic supply Vcc to diodes?

I have been studying the L298N motor driver module to re-implement it as an exercise to learn PCB design. Something I am confused by in the schematic of the module is why Vcc is supplied to the diodes ...
1 vote
0 answers
75 views

Amplifying electret microphones with wrong bias power

I have an issue. I'm making a device that can switch between two microphones for a two way radio. The microphone that comes with the radio is an electret microphone that gets its plugin/bias power ...
0 votes
0 answers
45 views

AC/AC power supply for PCB

I am trying to source the right setup for powering this PCB: I have found an 18 V AC/AC power supply but it has a barrel connector: I am struggling to work out how to connect the barrel connector to ...
0 votes
2 answers
58 views

How can I determine polarity requirements for a device that is missing its power supply?

I have a MASSFIDELITY relay, wireless Bluetooth receiver for which the power supply is missing. I found a manual for the device that states it requires DC 5V 1A power, but says nothing about polarity. ...
  • 11
4 votes
1 answer
186 views

Questions regarding this power module

I'm looking at this power IC module. I assume it's a buck converter. In that case, on page 16 of the datasheet, Equation 4.1, there's this formula: Rvout = 8.2 kΩ * TRIM. If TRIM is 5, then what would ...
  • 2,874
1 vote
3 answers
87 views

How to calculate the AC current consumption of an external power supply if I only know its DC volts and amps output

I'm working in an AV project and need to calculate the total AC current consumption of an AV equipment rack for the electrician to calculate breakers and the electrical installation, but some of the ...
0 votes
1 answer
73 views

How to take only a certain amount of power from one source when two power sources are connected in parallel

I want to output 12V 45 watts to turn on a 12V 45 watt LED (motorcycle headlight). The image given is schematic of my target project. I need to draw only 15 watts from the battery and the rest of the ...
1 vote
1 answer
25 views

Connecting 12 V RS485 appliance (soil sensor) to USB 5 V RS485 adaptor

I have a 12 V RS485 appliance that measures some soil resistance etc. It is a 7-in-one soil sensor, the 12 V version of the 5 V version shown in the link. I could not find a 12 V USB to RS485 adaptor ...
0 votes
1 answer
105 views

DC current measurement in a battery cell

I want to apply a fixed voltage (around 1.1V) to an electrochemical battery cell in order to remove some oxygen from it due to parasite processes that affects the battery operation. At the same time, ...
0 votes
1 answer
39 views

Powering ESP32S Node MCU through Vin vs USB

I am having a situation with my ESP32S Node MCU that I can't figure out. I uploaded a sketch to my MCU that will blink the blue LED connected to GPIO 2 every x number of seconds. Here is the sketch <...
-1 votes
1 answer
69 views

Powering MCU and LCD screen

I’m using a 7805CT to regulate power for an Atmega328p for a project with an LCD screen. At first I was planning on having the LCD screen connected to the output of the regulator as well until I ...
  • 1
9 votes
5 answers
2k views

Why are there two power sources for some amplifiers?

In this diagram the DC power sources for a linear amplifier are shown: We see there are two separate batteries connected to it, and then to ground on opposite ends. Why must there be two separate ...
1 vote
1 answer
57 views

How to set Vref on a variable power supply

I recently recycled a 070XF01 voltage regulator from an old PCB. I want to make a 5 V power supply for a small project to power an ESP32 dev board. I'm still new to reading datasheets and this has ...
  • 11
0 votes
2 answers
82 views

LM7805 decoupling capacitors

Would it be possible to replace these combinations of ceramic and electrolytic capacitors with just a pair of low-ESR 10 μF ceramics? Conversion from 12 V to 5 V, minimal consumption, only MAX485 ...
0 votes
0 answers
28 views

Bandpass active filter design with differential input

I want to make a bandpass filter with a differential input. The filter I wanted is ready, but I made it for a single input. How do I make this filter suitable for differential inputs? The filter I ...
0 votes
2 answers
66 views

Meanwell 24VDC (constant voltage) PSUs in parallel

Can we use constant voltage + constant current 24 VDC supplies in parallel as shown below (to meet higher current/power demand): Product link Datasheet I have two opposing thoughts and hence the ...
  • 7,596
1 vote
1 answer
58 views

External power supply for a microcontroller board

I want to power this Nucleo board by a 5V external source using E5V pin. But regarding the external power supply choice there is the following section: I was planning to use this 5V SMPS. I didn't ...
  • 588
0 votes
0 answers
37 views

Temperature protection in an SMPS

In some power supplies there is OTP functionality mentioned as in the example (from this datasheet) below: In this case, what does 80°C mean? Does it mean the PSU output will shut down when the ...
  • 588
0 votes
1 answer
38 views

Power supply issues for half-bridge IGBT driver

We are designing an isolated power supply for our IGBT Driver. We took the reference design from this & this This is reference design 1: This is reference design 2: We are using a zener diode (...
2 votes
2 answers
127 views

How can I power Raspberry Pi Zero / 3B in forest where I don't have enough sun?

I'm making an authonomous robot (like Phoenix probe but very simple and cheap and made for Earth, no moving parts, just sensors). It controlled by Raspberry Pi and will live in forest shadowed by ...
  • 143
1 vote
1 answer
74 views

Level shifter is injecting noise to ground

I have a camera core with a DVP interface which has 2.5 V data logic and the system I am using is 3.3 V level. So I have used a TI SN74AVC20T245 level shifter to shift 2.5 V to 3.3 V. The image from ...
2 votes
2 answers
109 views

AC-DC power supply burning relays

I use an Arduino to control a relay. This relay is on an 8-relay board. The relays are rated at 120 VAC, 10 A. This relay powers on and off an AC-DC power supply. It has 110 V AC input and is rated at ...
3 votes
3 answers
174 views

Problem with SMPS input

I had this Chinese adjustable 2 kW SMPS (0-24 V and up to 60 A) for few years now and everything was fine with it, but recently it let some smoke out and blew a fuse, it could still be turned on and ...
0 votes
1 answer
55 views

Relay rating explanation

Let say we have a relay rated for 12 VDC - 80 A This relay is connected to a 4 Ω load and a 300 VDC power supply (charged capacitor) for a few milliseconds. The current in this case is 75 A. My ...
11 votes
2 answers
278 views

Does PSRR improve with multiple LDOs in series?

Would having multiple LDOs with different output voltages are in series, for example: 5 V from a buck converter -> LDO1 (3.3 V) -> LDO2 (2.8 V), and assuming all LDOs satisfy the dropout voltage ...
  • 123
1 vote
1 answer
147 views

Triggering 120 MP3 players with an Arduino Nano and a 4066 chip

I have a circuit that sends a 300 ms signal (a short button press) from pin D13 on an Arduino Nano to a 4066 chip, which then sends it to 4 boards (A, B, C, and D). Each board connects to 30 MP3 ...
0 votes
1 answer
60 views

Quick reset technique of pulse transformer core

I am analysing a pulse transformer which is required to transfer below communication protocol pulse from primary to the secondary side. The pulse duration is 32 μs and off time available to reset the ...
  • 165
-4 votes
4 answers
78 views

Power supply for remote load

I tried to design power supply circuit myself because no power supply would do for me (or I'm just unaware). My issue is that I have power supply far away from load and there is no way I can shorten ...
  • 19
0 votes
0 answers
22 views

LLC Half-Bridge: How do I determine Qe_max?

How do I figure out what the value for Qe_max (curve 2) should be? TI's application note describes Qe_max as Qe at maximum load, and Qe is a function of the load, Re. I am confused on how to figure ...
0 votes
1 answer
71 views

What kind of temperature would I get with XL4015 voltage and ampere regulator converting 12 V to 6.5 V?

I have a guitar amplifier (Blackstar ID Core 10 v2). Its power brick has gone bad last year, and I have been searching for a power brick ever since. This device works with 6.5 V, 3 A DC. It is pretty ...
  • 3
0 votes
1 answer
47 views

Does peak mains power consumption of a laptop chargers depend on input or output parameters? [duplicate]

Disclaimer: I do understand that depending on the load the "power adapters" or chargers would pull a completely different values, so this question is about the theoretical "peak". ...
0 votes
0 answers
26 views

Solar charging- battery overcharging due to resistance of path voltage drop

I am trying to implement Solar charging for cells using LT3652, as mentioned by one of their modal circuit The circuit works for multi-cell chemistry while charging till the VFB voltage reaches a ...
3 votes
1 answer
252 views

Is the rated current on a component actually a fixed exact number, or is it more like a range in practice?

I have a circuit with 30 computer fans and a DC power supply and they seem to turn on and run well. The fans take 12V and their rated current is 0.18A. My power supply is 12V 5A. By my math, this ...
  • 131
2 votes
3 answers
62 views

Is there such thing as a load generator for testing a modular power supply unit?

I have built a modular power supply - and I was wondering if such thing exists to generate a mock load. I have two supply blocks and I need to make sure they are supplying adequate current. I can hook ...
1 vote
0 answers
33 views

Switching two relays using the same 1no1nc latching switch

I am working on a device to control power to some telescope devices. I am using a 12 VDC, 20 A power supply block; this will be switched using two relays (10 A each) to the load devices. I have two ...
0 votes
0 answers
35 views

Linear stabilizer surge voltage when raising current load

I'm building linear stabilizer with an output voltage from 1.5 to 35 V, but sometimes when I switch the load from low current (1 mA) to high current (11 A) at 1.5 V there is a surge voltage at the ...
0 votes
2 answers
115 views

Whole-house DC using PoE cheaper than multiple 5/12 V wall warts?

I have seen plenty of questions asked and answered about setting up whole-house low-voltage DC via something like PoE (passive over standard Cat5e cable, run through plasterboard walls). With the cost ...
  • 11
-1 votes
1 answer
62 views

Decrease DC voltage using resistors without decreasing current [closed]

How would one go about using a 12 V DC, 1 A power source to power something which needs 9.5 V DC, 1 A using resistors?
  • 1
2 votes
1 answer
90 views

Cost of pin insulators

H. Cotton's Transmission and Distribution of Electrical Energy states that the cost of pin insulators increases exponentially with voltage. Why is this, and why isn't it linear?
3 votes
3 answers
211 views

Does body diode reduce MOSFET switching loss in a power converter?

In power converters, it is common that MOSFETs are fed a PWM signal to have cyclic switching. Part of the power is lost in the process. Does the body diode reduce this loss? It seems most power ...
  • 529
0 votes
0 answers
44 views

Power 3 V or 5 V device only when AC device (induction plate) consumes power

I have a 5 V circuit with an Arduino using a current sensor (ZMCT103C) to monitor when an induction plate is in use, and then power on the ventilation (range hood). The 5 V circuit is powered by an AC-...
0 votes
0 answers
35 views

Auto switch between two DC power sources, depending on battery level

I'm looking for a way to use my Raspberry Pi on solar power when my solar-charged battery has enough power, and switch to the usual electric power grid when my battery reaches a certain level. I don't ...
  • 1
5 votes
4 answers
1k views

Where does the 3 V go in this circuit?

I have a simple circuit of a DC power source (15 V) powering a DC motor. There is a voltmeter connected across the battery terminals that reads 15 V when the switch is open. When the switch is closed,...
  • 51
1 vote
2 answers
131 views

Combine 2 rain-drop effect ICs

The image is from here. This circuit is to produce a beautiful rain drop effect as shown in the link. Is it possible that we can extend the rain LED to 20 LEDs instead of just 10 LEDs as shown in the ...
1 vote
0 answers
28 views

ACF flyback clamp current issue

I study a paper. There is a paper named "Design Consideration of MHz Active Clamp Flyback Converter with GaN Devices for Low Power Adapter Application" I have a question about why changing ...
  • 179
1 vote
0 answers
38 views

How do I construct my circuit with inputs connected to battery return?

I am trying to simulate my circuit and I need my inputs connected to my power supplies's returns or the negative terminal but now I am confused on what I would connect to the positive terminal and ...
  • 35
2 votes
1 answer
85 views

Increasing amperage of HP AC-063-2 A power backplane

The HP Proliant DL180 G6 has a power distribution board/backplane AC-063-2 A P/N 515766-001 with limits specified in the picture....
  • 133
-1 votes
1 answer
51 views

Using 12V output as ground in 24V power supply to form +/-12V rails

I have a power supply which outputs both +12V and +24V, Here's a photo: Can I use the +12V as ground in my circuit to have a -12V(from 0V)/+12V(from 24V) output? The load on the -12V output will be ~...
  • 1