Supply Definition and 515 Threads

Ok so i received the suggestion to get such a power supply by rigging a variac to a bridge rectifier, but variacs are rather expensive, so after some snooping around i came around this site: http://www.scribd.com/doc/9779212/ebook-free-energy-50000-vdc-power-supply they basically just use...

Hi, Can anyone help me to figure how to get 12V for the dc motor using 24V supply. I would like to use a 12V supply but that would mean some changes to the wiring. Instead of rewiring,I would like to just make do with the 24V supply. I will need a series resistor (ranging from 1k -...

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...

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...

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...

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...

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...

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?

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).

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?

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...

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...

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.

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...

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...

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

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...

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...

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

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

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...

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...

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...

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...

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

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...

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

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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 :)

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.

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?

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:

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...!:biggrin:

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...

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...

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...

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...

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...

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...

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

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...