What is Supply: Definition and 513 Discussions

In commerce, a supply chain is a system of organizations, people, activities, information, and resources involved in
supplying a product or service to a consumer. Supply chain activities involve the transformation of natural resources, raw materials, and components into a finished product that is delivered to the end customer. In sophisticated supply chain systems, used products may re-enter the supply chain at any point where residual value is recyclable. Supply chains link value chains.

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  1. A

    Bridge rectifier and symmetric power supply

    Could some one explain how a bridge rectifier works with a diagram and its mathematics? Also please explain how a center tap transformer and a bridge rectifier are used to provide a symmetric power supply. I have the Ckt Diagram for that but I cannot understand its working. thanks...
  2. T

    Compare burning of fuel to reversible supply of heat

    Hi! I'm working on a problem regarding a jet engine and I actually did solve it but I'm not sure about two things: At some point in the engine, air is heated at constant pressure (with the gas being almost stationary). Of course, this is done by the burning of fuel. But I found the...
  3. J

    PROBLEM: Turbine connected via adiabatic valve to air supply

    Homework Statement Air turbine used to drive a application in a machine shop is supplied with air from the factory air supply main where the conditions are 0.6 MN/m^2 and 31 ºCthrough an adiabatic throttle valve which reduces the pressure to 0.3 MN/m^2. In the turbine the air expands...
  4. D

    Figuring 12V 3A DC Power Supply Capacitance

    I want to know if I am figuring correctly. I am putting together a 12 volt 3 amp DC power supply. The formula in the instructions is C = Tc / R. I figured the required cap to be 20,750 uf. When I went to a couple of supply catalogs to check the price for the cap I found that no one had had a...
  5. D

    What is the best power supply for a peltier-based water cooling unit?

    Hi, I'm new here so I apologize if my question isn't composed appropriately. I’m currently designing water cooling unit, which is a component of a larger project, that utilizes peltier plates as a heat pump to displace the energy from the water. To cool the peltier plates themselves I...
  6. M

    Op Amp Current Supply - Is 3 Amps Too Much?

    Do opamps have current limit, I have an OP-27 dual supply connected to 2 9V batters the battery measures 3 Amps and 16 volts is this too much current?
  7. M

    Connecting Dual Supply Opamps in a Single Supply Circuit with Transistors

    I have a circuit with single supply lm324 and I need to replace them with precision opamps but I can only get dual supply ones. How would I connect the dual supply opamps in the circuit? (the circuit also has PNP and NPN transistors).
  8. S

    How can i figure the current loss of a power supply?

    OK, so if I'm inputting 120V ac @ 1.5A equals 180W and my output is 19V dc @ 3.16A equals 60.04W simple subtraction says 116W is left. that can't be right can it? am i doing this wrong or am i actually losing 116W of power?
  9. H

    Can I Safely Use 3.16 Amps with My AC/DC Laptop Power Supply?

    Just a quick question for you guys out there. I have an AC/DC laptop power supply. I was thinking of using it for a few projects. Th power supply's output is 19 volts and 3.16 amps. My question is is 3.16 amps the max current that the power supply can take without frying? I mean the number of...
  10. C

    How to reproduce a battery with a power supply

    I am expermenting with a sperical metallic neodymium magnet ball that spins like a DC motor when I hook up a + or - charge up to the north or south pole of the ball and then hook up the other charge to the equator of the ball. I have only used alkaline batteries and it works with a AA 1.5 volt...
  11. wolram

    Circuit diagram for a power supply that outputs about 25kv

    Does anyone have a circuit diagram for a power supply that outputs about 25kv at a few mA dc. 25kv is just a ball park figure it could be 22 or 30 kv, or even better adjustable from 22 to 30. Input would be 230v ac Thanks.
  12. C

    Constructing My First Power Supply: Investigating AC Components

    Ive recently completed a project in microcontrollers (my first project with uc's actually) and I built a power supply which gives me 12v and 5v dc. I use a transformer to step the voltage down to 12v AC from mains and then the 12v AC is converted to 12v dc using a bridge rectifier with a...
  13. P

    Full-Wave Bridge Rectifier Filter + Regulator DC Power supply

    http://img104.imageshack.us/img104/3557/1234uyq.jpg Ok, there are a few calculations on this problem that I am having difficulty with. This is a past homework assignment which is why the answers are filled in. They are all correct. Anyways I approached the problem in this manner: V...
  14. N

    Powering 150 LEDs with a 12v,1A Power Supply

    I am trying to figure out a better way to power 150 leds that need 3.4v and 20mA with a 12v,1A power supply. Right now the best way I can think of is have 3 leds in series and a 100 ohm resistor at the end(50 times). Is their any better way so I can use less resistors
  15. C

    How can you tell that this iron operates using the mains supply?

    Hi, I'm new to the forum so i don't really quite know what I'm doing yet! anyway, i know this question is REALLY basic but physics is not my forte and I'm confused... "John has just bought a new iron and sees this plate on the handle - 230V 1840W 50Hz" John irons a shirt for 10s...
  16. I

    Which voltage option for single phase supply?

    I am buying a high speed spindle from a company in Italy. They have two different voltage options available for the spindle which are either 220 or 380. I operate my CNC router using a single phase power supply. Can anyone confirm which voltage option I should go for. My business is located...
  17. X

    Connecting 460V Motor to 480V Supply - Issues & Risks

    Is it against code in any way to have a 460v motor connected to a 480v supply voltage? What problems can be encountered when doing this? Thanx
  18. J

    Optimizing Water Supply System Design for High Demand Scenarios

    can anyone tell me how to find the pressure head and residual head? the Q is depend on which?
  19. C

    3 phase equipment on 1 phase supply

    I was given a 3 phase plasma cutter (no motor in machine only transformers)and my garage is only 1 phase. I have been doing a little research on converting 1 phase to 3 phase but it is just to expensive for my budget! I did come across an article that suggested that is can be done without a...
  20. A

    Can a common 9V power supply be used as a -9V supply?

    So if you have something like this: https://www.amazon.com/dp/B0002H07CW/?tag=pfamazon01-20 can you use it as a -9V supply? My circuit requires a +9V and a -9V supply, and since I am having issues finding fixed +/-9V supplies, i was wondering if i could just use a 9V supply for the +9V, and...
  21. B

    Probability: supply and demand

    Homework Statement A replenishment order is placed to raise the stock level of a given product. The current stock level is s units. The lead time of the replenishment order is a continuous random variable having an exponential distribution with a mean of 1/m days. Customer demand for the...
  22. A

    Question about wiring from a power supply

    I'm considering using this power supply: http://salestores.com/pr30trouposu2.html now.. if i wanted to get a voltage value of -5V into a circuit (such as http://www.tekscan.com/images/flexi-circuit-new.jpg" ), could i just put a wire from the (-) terminal of the power supply, to the Vt? And...
  23. H

    Determining supply current/voltage to LED

    Bearing in mind safety margins, how much current and voltage should I supply an LED if it's rated as such: Forward current max: 25mA Forward voltage max: 2.5V Reverse voltage max: 5V Light output min.@ 10mA: 70mcd Light output typ.@ 10mA: 200mcd
  24. A

    Need a negative voltage from a 0-60V power supply

    I will have to power the following circuit: http://www.tekscan.com/images/flexi-circuit-new.jpg I assume I can just hook the (-) terminal to the -9V input, the (+) terminal to the +9V input, set the power supply to 9V, and then toss a resistor between the -9V and the -5V? Would that...
  25. R

    If I install stronger PC power supply in terms of watts

    ...than my current unit,is there danger that some component in my PC will be destroyed?
  26. G

    Transformerless AC to DC power supply

    Help! I was trying to build an AC to DC power supply circuit without using transformers. I followed the circuit diagrams given online, which has the 240VAC connected to a resistor at the live and a full wave rectifier whose output was connected to a capacitor and a zener diode. The figure is...
  27. G

    Design Regulated Dual Supply w/uA78L05 for Research Project

    I am trying to build an opamp array to amplify some voltages simultaneously. The amplification part has been designed. But now I am trying to design a Regulated Dual Supply for all the opamps. I found this circuit diagram in the Texas Instruments datasheet for uA78L05. This diagram shows an...
  28. B

    Building a lab power supply from a computer

    I found this link and thought it may be of some use to build a power supply. I know that these power supplies can pack around 500W on the right power supplies. Is there anything I should know and be careful of when making this and when playing with smaller electronics...
  29. C

    How do I safely build a variable DC power supply for my electronics projects?

    I'm taking an intro electronics class and I'm really enjoying it. I want to be able to work with electronics in my garage, I have a proto-board and but I would like to build a power supply that can go from 1vdc to 15vdc, this is what my class has. I've looked on the net for instructions, but...
  30. M

    Synchronous Motors: Can Rotor Spin with 3-Phase AC Supply?

    Hi, I have a question about synchronous motors. If the DC field winding of a synchronous motor were to be replaced by a low-impedance short-circuited coil and the stator were to be supplied with 3-phase AC, would the rotor spin? If the answer is yes, would the rotor follow the direction of...
  31. R

    24V to 5V Power Supply Solution for AVR & Other Stuff

    I have a 24 V lead acid battery that I am going to use for a power supply. I need to get 5 volts so that I can power an AVR some other stuff. I was originally intending to use a 7805 to get 5 volts, but I am concerned that this may be too much power dissipated. I think I need about 200-300 mA...
  32. G

    Equilibrium Price & Quantity of Supply & Demand Qs

    Given p is the price for buyers and p-t be the price that suppliers get after paying a tax per unit of t Supply is 2(p-t) and Demand is 100-p a.) what is the equilibrium price ? b.) how many quantities are sold at this price? i'm stucked with the first one , all i know is that when it is...
  33. F

    What is the purpose of a dual adjustable DC power supply and how does it work?

    hello , DC (I guess AC too) power supplies have 3 terminals: plus, ground, minus. If I set the voltage to 30 Volts, and plug one cable in the + terminal and the other in the - terminal, is the voltage across the wires 30 volts or 60 volts? When do we use the ground or the negative? I...
  34. X

    Single phase ac motor on dc supply?

    ive got a single phase ac motor that runs on 110V and i'd like to run it on a 12v dc source. basically its a transfer pump for a school bus that runs on vegetable oil, and we currently have to find an outlet to plug the pump into every time we go behind restaurants to fill up our tank. id like...
  35. G

    Find High Voltage Power Supply on a Budget

    Hi guys, I have been wanting to many electrical experiments over the last few years that need a high voltage power supply, till now I havnt found one suitable for me and thus wondering if anyone here on the PF has any suggestions. I don't exactly have a large budget, In fairness I would like to...
  36. D

    How to Construct a Variable-Output Current Supply Using Op-Amps?

    guys, i need some help... is it possible to construct a variable-output current supply using op-amp(s)? if so, can anyone help me about how to construct one? thanks :)
  37. G

    Effects of Increasing Supply Voltage on DC Motor Back EMF

    If i have a series DC motor and at say X rpm it has a back emf of 11.5v and supply voltage of 12v and i increased the supply voltage (keeping rpm the same) would the back emf stay the same? and if not would the diffrence between back emf and supply increase? Thank you.
  38. M

    Power Supply Failure? PC Won't Power On

    Hello, My PC stopped working a little while ago, and I think the power supply went out, but I'm not sure. It will not power on at all, but the light on my motherboard is still lighting up. Is this most likely a problem wih the power supply?
  39. N

    Can anyone supply me with a picture of

    a molecule? I'm looking for a background to my A1 research poster. It has to do with molecular spectra... It needs a resolution of more than 3000x3000. I've looked everywhere!:frown:
  40. 4

    Troubleshooting Computer Power Supply Issues

    my power supply for the computer has just burnt resently for the second time in less than twom weeks i obviously have to buy anothr one but am a bit hesitant cause i can't figure out y they keep burning nd the fault is not with my plugs please help wer u can...!:yuck::biggrin:
  41. P

    RLC Circuit - AC Power Supply

    Homework Statement The figure below shows the time variation of the current through an electrical heater when it is plugged into a 240 V, 50 Hz outlet. 1) What is the peak voltage? 2) What is the rms value of the current drawn by the heater? 3) What is the resistance of the heater...
  42. E

    DC power supply with DE-9 connection

    I have a photodiode/amplifier module, which has a D-sub connection for the power supply. The manufacturer sells a power supply, but it is out of my budget range, and the lab only has standard laboratory PSU's (+V,-V, gnd). Is there any connections so that I can use this module with my power...
  43. †

    Dual output dc power supply questions

    Hi, actually someone already posted the same questions but I thought it would be weird to continue from that post as I have a lot of questions of my own. The assignment requires me to draw a schematic diagram of a dual output dc power supply, identify the sub sections that make up the power...
  44. G

    Can You Safely Use a Center Tapped Transformer for a Dual Polarity Power Supply?

    I'm designing a set of voltage and current sensors for use with a solar system. I have developed all of the circuits, but it requires both positive and negative voltage supplies. I want to use the classic design using a center tapped transformer with two regulators. But I'm not sure what will...
  45. R

    Dual polarity power supply circuit question

    I'm having trouble with the power supply portion of an opamp circuit I'm working on. The supply is +/- 5 Volt using 7805/7905's. Half wave rectifiers provide the unregulated input with 1000uF input caps and 100uF output caps. AC is supplied by a 13VAC 'wall wart' with no center ground tap...
  46. U

    Connected the capacitor to a DC power supply

    A few days ago, I was in the lab doing some experiments with capacitors and something weird happened... I connected the capacitor to a DC power supply and after a few seconds the capacitor has popped. The voltage applied to it was within its working voltage, so that was not the cause. My...
  47. N

    How to Create a Battery-Operated +/- 15 Volt Power Supply for Op Amps?

    I need a battery operated +/- 15 volt power supply. I'm going to use it to run a couple op amps. Any help with a circuit? Thanks
  48. J

    Supply & Demand: Grain Production Increases and Prices Remain Low

    Improved grain production methods and increased acreage have more that offset population increases. As a result prices remain low for grain. Describe how this would be interpreted on a supply and demand diagram. Here's what I have so far: -demand decrease, supply increase -price decrease...
  49. J

    Supply & Demand Impact of SW US/Mexican Freeze: Prices Rise for Imported Produce

    A freeze in southwestern U.S. and Mexican fields has resulted in damaged crops and inflated prices for imported produce such as lettuce, broccoli and cauliflower. Describe how this would be interpreted on a supply and demand diagram. Do not draw graph. *Please include one(if you can) so I...
  50. J

    Creating a Portable 6V 1A Battery Power Supply for a Modem: Where to Start?

    I'm trying create a battery power supply to create a portable modem. The modem runs off an AC wall adapter, and on it, its written to have 6V 1A output. My power supply needs to have the same output characteristics, but be battery powered. Can someone please point me in the right direction? Thanks
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