What is Power supply: Definition and 301 Discussions

A power supply is an electrical device that supplies electric power to an electrical load. The primary function of a power supply is to convert electric current from a source to the correct voltage, current, and frequency to power the load. As a result, power supplies are sometimes referred to as electric power converters. Some power supplies are separate standalone pieces of equipment, while others are built into the load appliances that they power. Examples of the latter include power supplies found in desktop computers and consumer electronics devices. Other functions that power supplies may perform include limiting the current drawn by the load to safe levels, shutting off the current in the event of an electrical fault, power conditioning to prevent electronic noise or voltage surges on the input from reaching the load, power-factor correction, and storing energy so it can continue to power the load in the event of a temporary interruption in the source power (uninterruptible power supply).
All power supplies have a power input connection, which receives energy in the form of electric current from a source, and one or more power output connections that deliver current to the load. The source power may come from the electric power grid, such as an electrical outlet, energy storage devices such as batteries or fuel cells, generators or alternators, solar power converters, or another power supply. The input and output are usually hardwired circuit connections, though some power supplies employ wireless energy transfer to power their loads without wired connections. Some power supplies have other types of inputs and outputs as well, for functions such as external monitoring and control.

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  1. C

    Calculating Charge for Replacing a Power Supply in an Electric Field Experiment

    Homework Statement In lab we did an experiment where there was a 12v D.C. power supply in a glass dish filled with water. We set the + and - terminals in the dish and a piece of graph paper underneath. With a volt-meter we hunted for certain electric potentials such as 2V, 4V, 0V, etc and wrote...
  2. S

    Can I replace damaged capacitors in my power supply with a 1000uf cap?

    The monitor/ tv will power on for around 30s and i can see all the icons on the tv but then will shut off I'm thinking its the power supply so i took a look at it and 3 of the capacitors look bad i have no clue where to get capacitors in the Harrisburg Mechanicsburg are. I don't want to buy...
  3. X

    Basic Power Supply: Design & Connections

    Hi, I have to build a very basic power supply, basically from a 220V AC Wall socket to a certain DC Voltage as the output. I plan on using a transformer, rectifier,capacitor and a voltage regulator. I can see that following this design it can only give out one value of voltage. I thought of...
  4. M

    Need help choosing suitable power supply for DC motors

    Hi everyone, I need a suitable power supply that runs off 240VAC (a regular mains socket found at home) to power two DC motors in parallel. The motors are each rated at 24V, and have a full load current rating of 15A. I've performed a search, but the power supplies I've found are either...
  5. R

    Creating 300VAC for 3 Phase Variable Frequency Drive Testing

    Hello all, I have a 3 phase Variable frequence drive that requires an input voltage of 380-480VAC. I would like to test what would happen if I apply 300VAC to the drive. I have access to 208V and 440V. Is there anything I can do to obtain 300V? I have thought about a variable power supply...
  6. A

    Tube amp power supply question

    I have a US Navy "Plate and Filament Transformer" Manufactured by Hudson American Corporation. This monster weighs 14.5lbs, and is in a sealed steel casing. My output trans weighs 15.5lb as well. There are 16 unlabeled terminals, and I'm working to identify those. Suggestions on how to go...
  7. E

    12V / 6A Power supply. Help with Buck and Boost converters + OR'ing circuit

    Hello all. Maybe someone here can give me suggestion of ICs and make considerations about this design. The attached picture states how this power supply should work. Details: 1) IC 1 probably will be a LT3650-8.4 from Linear Technology. It supports up to 32V of input voltage (40V peak)...
  8. wolfspirit

    Power supply for electromagnet

    hi i am wanting to make an electromagnet as a project and i have ordered 916 meters of 0.125mm ENAMELLED COPPER MAGNET WIRE. i am a electronics hobbyist but i have not played with bench top power supply's before and i don't know where to start what is the best/ safest or how to use them...
  9. C

    Need a stable 5V 7A Power Supply

    I am trying to power 230x Laser diodes at 30mA each. Applying 5V to each would accomplish this. However, I've converted two PC Power Supplies to general purpose power supplies and neither of them were able to support the required current. They would drop from 5V to maybe 3.5V at around...
  10. C

    Increasing power supply to building

    I have a warehouse (industrial building) which has a 5killowatt/hour output. This is a 3 phase supply. I need to increase it to at least 10killowatt/hour. The electrical system is modern. But do I need to change the infrastructure to increase the power output? If I need to change the...
  11. Link

    Peltier Cooler connected to Power Supply, is this configuration safe?

    I am building a Peltier Cooler with the circuit diagram below. The power supply will be a battery, but for testing purposes I am connecting it to a stationary power supply. http://dl.dropbox.com/u/10419947/circuit.png I suspect that the peltier coolers which are rated at 30A will draw as...
  12. M

    Isolating and Protecting Your Microcontroller and Motor with Shared Power Supply

    Would there be any fear if I supplied both the microcontroller (through a voltage regulator) and the 12V DC motor using a driver connected to the microcontroller from the same 12V source? Current will be distributed on both the motor and the controller and some other circuits interfaced with...
  13. A

    Question about Kepco Power Supply with Error Sensing

    Hi, here are a few newb questions about error sensing - I have a Kepco BOP 20-10M that I have connected to a solar cell. The purpose is to sweep voltage across the cell and create I-V curves. Attached is a screenshot from the manual showing the setup for my application - using error sensing...
  14. N

    Power Supply Amperage Question

    Hello. I am trying to wire 40 LED bulbs to a power supply i bought with them. Each bulb has a forward current of 100 mA. So, I calculated I would need 4 amps of current to power the lights if I wired them all in parallel. However, the power supply I purchased Says 12V DC 12.5 Amp. Is that...
  15. E

    Power supply using a voltage regulator?

    I would like to inquire if a voltage regulator maybe used as a power supply to a system. I am not very familiar with EE stuffs so any help would be appreciated :) Our system consists of aluminum metal plates submerged in water. It needs to be supplied with 10A (DC) thru the portion of the...
  16. A

    Which H-Bridge driver can I use for power supply amplification?

    I have been tying to design and build a dc to ac inverter. I want to convert 10v dc to 25v ac @ 50hz. I want to use a pic24h microcontroller to generate pwm waveforms to control a H bride driver. I have programmed the pic24h to produce pwm waveforms. I used the LMD18200 as the h bridge driver...
  17. A

    Power supply and power dissipated in a circuit

    Can Power supply be smaller than power dissipated? Because I saw this in one question There are 3 cells, the power supply of the two 4V cells cancel each other. (one is -4W and another one is 4W) So the total power supply should be 16W But in part c, the power dissipated is 4+8+2+6=20W...
  18. L

    What is the internal resistance of the power supply

    A 76 W light bulb with a resistance of 179 Ω is connected to a power supply with a 117 V. What is the internal resistance of the power supply? Express the answer with one decimal place. So my attempt has been this but I'm not exactly sure whether or not so just making sure this would be...
  19. O

    Unraveling the Mysteries of USB Power Supply: Is it Just 5V or Something More?

    Hello. This is probably a silly question. But it is something I haven't been able to find an answer too. When I connect something to my laptop through the USB, I know that there is 5V coming from the USB connection ...there are many pinout diagrams about that show this. But what is the...
  20. J

    Design Dual DC Power Supply: 0-20V, 0-1.5A, User Selectable

    Hi,i really need help on how to design a dual channel DC power supply that fulfills the following specifications : 1) Operation - User selection between independent adjustment for positive and negative output voltage, and series tracking mode (slave channel tracks the master channel) 2)...
  21. S

    External Power Supply or Put Regulator on Main PCB?

    I'm close to finishing my first 4-layer board. Initially, we felt that keeping the power supply as a separate unit would be better. This was because we wanted to avoid having heat on the main PCB - mostly because the area where the device is intended to be used is very hot and also quite dusty...
  22. M

    Very specific question on current draw from a dc power supply

    okay so I am just slightly confused about current and about how it is drawn from a power supply, so say we have a device that requires 5 volts and uses a max of 550 milliamps, and now let's say that the power supply used is rated at 5 volts, but 32 amps, does this mean that the power supply...
  23. F

    Building an AC to DC power supply

    I'm building an AC to DC power supply for a class and my question mainly revolves around the input and output of the whole thing. My source of confusion is where to include my DC output in a circuit such as I would assume that it would be the leftmost node of that full bridge rectifier...
  24. L

    What is causing the 0.7V voltage drop across the capacitor?

    I have this arrangement where 0.45V supply and 5v supply are connected to a load (say 6k resistor). The 5V source is forcing current to flow into the 0.45V supply. This is a bit counter intuitive. Power supplies usually source current. Ckt schematic attached.
  25. I

    Can a Step Down Transformer Handle Universal Input for a Linear Power Supply?

    Building a simple linear power supply for a project and need to spec out a transformer. I have no idea how they're built and used in the industry. I was instead handed a 120VAC input with a 24VAC output and 2A max step down transformer. I am content with it for the moment. But I'm looking to...
  26. F

    30kv .3mA DC power supply tips?

    Hello, I interesting in making a high voltage power supply for capillary electrophoresis. Not much power is required and the DC does not need totally noise free so I figure this gives me a lot of flexibility. I would love the ability to adjust the voltage at 5kv increments in maybe a 5-30kv...
  27. B

    Reusing Old PC Power Supply: Making Voltage Source & Safety Tips

    Hello, I just stumbled upon an old PC power supply. I thought it would be a good idea to reuse it. I am thinking making out of it a simple voltage source, as it is already voltage source. Can somebody explain me how can I safely get that voltage from those hanging cables that go into HDDs, CD...
  28. P

    How to get a dc power supply to produce 2V at 10-20 milliamps?

    I just got a adjustable dc power supply and I cannot figure out why it will not produce 1-2V at very small amps such as 10-20 milli amps? Is this not possible with a common dc power supply? I would greatly appreciate some help with this...
  29. A

    Making a 5V DC Power Supply for Microcontroller: Possible Damage?

    i want to make a 5v dc power supply for microcontroller i know how to make it i am going to use a 220v to 15v transformer and then by using capacitor and 7805 regulator ic i will convert it to 5v my question is as in transformer pout=pinput (ideally) by decresing the voltage from 220 to 15...
  30. A

    Designing a Voltage Regulated Power Supply

    Homework Statement A voltage regulated power supply consists of a full bridge rectifier feeding into a filter capacitor, and then into an NPN bipolar junction transistor (BJT) operating as an emitter follower, and with the base of the BJT biased using a resistor and a zener diode. The power...
  31. L

    Shore power supply for the vessel

    Hi all, I am facing the problem with shore power supply for the vessel. At our ship yard, sometimes we need to arrange temporary electric supply for the vessel meanwhile their generators are overhauled. For 440 V 60 Hz i am using portable generator supply and for 415 V 50 Hz supply i am...
  32. M

    Help Fix RCCB Power Supply Issues

    Hi, I got a problem and seeking for help, could anyone do me a favor. The power supply of network data centre is supplied by a UPS. The UPS’s output connects to 2 nos. of 800A MCCB individually. And the circuits are protected by: ( Form >> to ) A) 800A MCCB >> 100A MCCB >> 100A AI...
  33. C

    Power supply and Multimeter questions

    When measuring voltage or current, why are we suppose to crank up the power supply? For example, when we are measuring voltage we are supposed to make sure sure the current is set high enough so it won't limit the voltage, and vice versa for measuring current. I thought if you crank up voltage...
  34. Evil Bunny

    Fixing Noisy Power Supply Issues

    "noisy" power supply? So, there was a high pitched sound coming from a component (a radio, not sure if it was a transmitter or a receiver)... An experienced technician said that it sounded like a bad power supply... He mentioned something about a bad capacitor. The power supply was changed...
  35. B

    Hooking up 24vdc power supply to motion controller

    Greetings. I am asking for help connecting a Wago 24vdc power supply to a Galil motion controller. I have a very limited electrcial background. The power supply (ps) has 120vac L-N-G inputs (I get that part) and outputs 24vdc/2.5A as two plus (+) outputs and two minus (-) outputs...
  36. N

    Amp dangers from a universal power supply adapter

    I have a treadmill that has a display monitor that uses either 4 D cell batteries or an optional adaptor. The back of the monitor states it uses a 6v 1.66-2.0a/max input. I purchases a universal power adaptor that has a fixed amp rating of 3 (6v obviously is an option). The question is: what...
  37. J

    Cancelling out Power Supply Noise out COMPLETELY

    Hi I have a HV (R2) resistor that I want to test for noise. Assuming the 2 low voltage resistors are perfectly stable and HV R1 is also perfectly stable. How could I completely cancel out the noise of the power supply if the bridge was slightly unbalanced? Does any circuit exist that can do this?
  38. G

    Understanding Power Supply and Ethernet Adapter Wiring: A Guide"

    I'm trying to hook up my power supply to I/O Ethernet Adapter, and am getting confused with the wiring terminology. The power supply is 24V DC (+/- terminals) and the Ethernet Adapter has NC, Chassis Ground, Common (C), and V (Supply). I guess I am getting confused with what exactly Common...
  39. K

    Designing a power supply with a center tapped-transformer and a zener diode.

    Homework Statement Design a full-wave regulated power supply using a 5:1 center-tapped transformer and a 7.5 V, 1 W Zener diode. The power supply must provide a constant 7.5 V to a load varying from 120 to 450 . The input voltage is 120 V(rms), 60HZ.Homework Equations The Attempt at a Solution...
  40. N

    Charge bateries with regulated power supply

    I have a 230V to 13.8V / 20A DC regulated power supply and two 12V / 50A car batteries. What circuit must I use between them to charge the batteries and how long it will last the cycle? Thank you
  41. A

    Power Supply Output: Connecting + and - to Plates

    I am trying to make a capacitor by connecting + and - to the electrodes between two parallel plates. There are + and - and Ground in the power supply which of these should I connect to the two plates and how does it work. thanks
  42. H

    Need help raising the voltage on a power supply that I am making.

    I am currently building a DC power supply for a HHO Fuel cell. I am looking for HIGH current at a relatively low voltage (12-15 volts). I already have modified a MOT (Microwave oven Transformer) for high current. I replaced the high voltage secondary with 3 secondaries each consisting of 12...
  43. Y

    I have two transformers of rating 500 KVA. Power supply avaiable is 11

    I have two transformers of rating 500 KVA. Power supply avaiable is 11 KV. what size of HT cable should I use?
  44. T

    Using a Power Supply - Questions & Answers

    Um, so I'm building this power supply but I am somewhat new to a lot of actual electrical devices... I have a precision power supply unit. There is an AC voltage option and a DC voltage option. Within the AC voltage are there are three terminals. The outer two are yellow and marked...
  45. H

    Voltage regulator (from power supply) capacitor values?

    Hello our doctor gave us a project to design a power supply which looks like this http://i541.photobucket.com/albums/gg395/healing1000/powersupply.jpg however at the voltage regulator part (78xx and 79xx) there are 2 capacitors (the 2 on the right) which I don't know how to find their values...
  46. P

    Bench Power Supply With Microcontroller

    I know this question is so simple and probably stupid that it will enrage some people, but bear with me. :) When connecting a bench power supply that does 5V@3A, to let's say a P16F88, should I use 25 ohm resistor to bring those 3 Amps down to 200 ma? According to the p16f88 datasheet...
  47. Y

    How to connect 11v Battery to 5.3 V power Supply

    Hi friends, I don't have any electrical background. In my experiments I have 11 V Battery which has to power up PC104 which needs 5.3 V. Can please help me out how to step down the voltage. Thank You, Yawanth
  48. G

    Wiring a 115/230 VAC Power Supply Without a Wall Plug

    I have a power supply with an input of 115/230 VAC. There is no wall plug wired to it, just cut wires. I don't have much experience with this. If I wire this to a cord can I plug it into the wall (120 volts)?
  49. PainterGuy

    Maximum rated voltage/current value on lab power supply

    Hi :smile: While helping me with the queries please don't forget that I'm a beginner to this technical stuff (or, my knowledge of this area of knowledge is nothing more than beginner's! :) ). I'm trying to understand how simple lab current source and voltage source works without getting...
  50. U

    Current limited power supply and Ohm's law

    Suppose I have some resistor with resistance R. Using a typical power supply, application of a voltage difference V across the resistor leads to a current draw of I = V/R according to Ohm's law (so long as the only circuit element is a resistor without any complex impedances). Now, suppose I...
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