Entries Tagged 'standard Ac Power Supplies' ↓

Hello,

I am looking at building an led circuit with ten 3 watt leds, with a forward voltage of 3.7v (700ma), will be using a constant led driver (may be more than one if required). the drivers can have an input supply of 24vdc, and require 1.5v to power them. so by my calculation i can have 6 of these leds on one driver.

24 – 1.5 / 3.7 = 6.08

24 is the input voltage.
1.5 is the voltage the drive needs.
3.7 is the forward voltage of each led.

so i would like one power source for the two drivers, how do i calculate the output wattage that will be required from the power source?

Cheers Gordon

I've got a JNC 1Gb flashdisk/mp3 player and would like to connect it to my car by converting the car's power supply to a 5V DC supply. I am able to listen to my mp3's through my headphones when it's connected to my computer (via USB port) and I know that the supply voltage is 5V (with a 5% tolerance) I'm just scared that an external source might damage my flashdisk due to internal impedance or so? Can i take that risk??

Hi,I designed a power supply board which is powered by a 12V transformer connected to a full bridge rectifier. The rectifier drops ~2 volts and considering the voltage of the supply main etc I get 9.5 – 10V output from the rectifier.

The output of the rectifier I connected to a 7805 IC and I get 5V Output. I connected a 220 uf cap accross the + & ground terminal and get ~5.25V. I also have a 24v rectified source, the 12V and 24V ground are connected.

I connect this supply to a board a) which contains 2 microcontrollers, 1 16x2LCD,board b) which contains 4 5V relays , 4 LM339 ICs and 8 3094 power transistors.

The problem is there is a very heavy dip in voltage when I connect to each of the boards, each microcontroller dips nearly 1V so when I put in my second microcontroller the voltage dips as low as 3V and the case becomes worse when I connect the supply to the other source.

I need to have common ground thro' the 2 boards.
How can I prevent the voltage from dipping down and maintain a constant 5V?
Can any one please give me a solution to this problem?

You need a capacitor across the output of the rectifier. You are applying what is known as "pulsating DC" to the regulator, and that won't work.

Put an ADDITIONAL 220uF cap across the output of the rectifier to ground.

Actually, I wonder if you need the 220uf across the regulator output . . maybe something smaller would work, like maybe a 10uf tantalum. BUT . . .do what the specs for the 7805 say.

AND . . .I was wondering if the 7805 has enough power capacity to handle all that you're driving. You need to measure the total current draw on the 5V line. You might try inserting a voltage sensing resistor (1 ohm/2 watt) in series with the 5V line and measure the voltage drop across the resistor, then figure current using Ohms Law. Or you could just break the 5V line ans insert an ampmeter in series.

Makeu sure you are not exceedign the apability of the 7805.

You're only getting 9.5 to 10V from a full bridge rectifier? that cannot be right.

You should be getting 12V (ac) from the transformer alone. You feed this into the rectifier and then a big electrolytic capacitor across the +ve and -ve terminals to smooth the DC output of the rectifier.

Do you have an oscilloscope to check waveforms? Only it is sounding like one of the following problems:

1) Missing electrolytic capacitor, or bad connection to it, or it is open/short circuit.

2) not getting full rectification for the rectifier, a half-wave rectification might give about the voltage you are getting. Check wiring, soldering and finally check for a faulty rectifier.

3) are you overloading the transformer with a near-short circuit, or circuits that are trying to draw far more current than the transformer can supply?

Good luck finding the problem and I hope it helps…

You should get 15 volts DC from the bridge.

You probably need a large cap across the output of the bridge rectifier. try 20000uF to 50000uF (rated at 20 volts or higher). Measure the AC voltage at that point, it should be less than 0.5 volts. If not, make the cap larger.

Or your supply is being overloaded. Check the current out of the regulator. It should be within the ratings of the transformer and of the 7805, and of the diodes.

Check the temperature on the 7805, it may need a heat sink. The part will shut down if it overheats, and that may be what you are seeing.

Check the wire size you use for grounds and +5. use #20 at least.

.

This is a voltage converter or transformer that can be used as a step up transformer in 110/120 volt countries or as a step down transformer in 220/230/240 volt countries. this heavy duty voltage transformer can be used for continuous duty. It will convert voltages of 220-240 volts to 110-120 and will also convert voltages from 110-120 to 220-240 volts.Amazon Sales Rank: #366 in Lawn & Patio Color: Black Brand: Power bright Model: VC500W Dimensions: 4.10″ h x 4.70″ w x 5.90″ l, 500 watts continuous power On and Off Switch 2 Spare Fuses Included FREE Grounded Adapter Included Heavy Duty500 Watt Voltage Transformer (VC500) this voltage converter can be used in 110 volt countries and 220 volt countries. It will convert from 220-240 volt to 110-120 volt AND from 110-120 volt to 220-240 volt.Very helpful customer reviews 2 of 2 people found this review helpful. Works great, includes spare fuses of EdTice a transformer is a device conceptually simple and has never had a different model, so it can not be compared. However, I can say I was very pleased with the product comes with extra fuses. the case is metal, not plastic. I like the tension is set with a bridge .. not accidentally hit a switch. as you see in the picture, the 220 can handle most configurations of the contact. August 6 people found this review helpful. Does not work. by Tim Gladding picked up this box to run any electronic equipment in the UK, here in the U.S.. the product claims that the production of 220 A / C 110V A / C. there is a manual feature has to move around in the back (OK) to match the input voltage, but despite this, the processor has only been able to input 120V to 110V and 220V outlet on the front. the "Documentation" is a single page misspelt broken English that gives you no clue what the problem could be It includes such gems as: "Make sure the transformer SWITCH If" Off "" "if you use this NORTHERN TRANSFORMER Eurpoe "It seems that the only solution to this problem that Amazon can offer is to replace it with another. he weighs 8 pounds, I hope they cover the shipping back defective. 0 of 0 people found the following review helpful. Trusted by Julian Lewis I got this adapter to my 400 watt U.S. rice cooker, which is 110 volts to 220 volts here in France run. It works perfectly, small and quiet. I recommend it as a transformer down. see all 4 customer reviews ….

Three-phase 5KVA variable frequency power supply 50HZ / three-phase 5KW variable frequency power supply 60HZ

Brand: The male genital is great

Name: Three-phase 5KVA variable frequency power supply 50HZ / three-phase 5KW variable frequency power supply 60HZ

Type: YF-650

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The products are detailed:

The speciality of Limited Company of great variable frequency power supply of male genital of Taiwan is researched and developed, produce, sell the variable frequency power supply, single-phase variable frequency power supply, three-phase variable frequency power supply, exchange the variable frequency power supply, variable frequency power supply of Shenzhen, the intersection of high-power and variable frequency power supply, the intersection of 60HZ and variable frequency power supply, the intersection of 40HZ-499HZ and variable frequency power supply, the intersection of 0-300V and the intersection of voltage and adjustable variable frequency power supply continuously, male genital’s great variable frequency power supply. welcome the incoming telegrams of trade company to order. The product series of our company: 1.Enter only and go out of the variable frequency power supply only: Output power: ( 500VA-120KVA) ,Output voltage 0-150V/0-300V) ,Output frequency ( 40HZ-499HZ) 2.Three enters to go out of the variable frequency power supply only: Output power: ( 3KVA-300KVA) ,Output voltage ( 0-150/0-300V) ,Output frequency ( 40HZ-499HZ) 3.Three stock 3 variable frequency power supply: Output power: ( 3KVA-300KVA) ,Output voltage ( 0-260/0-520V) ,Output frequency ( 40HZ-499HZ) The electric parameter of the variable frequency power supply: Input the frequency: 50HZ, 60HZ or 400HZ Output frequency: 40-499HZ means the pulling out type is continuously adjustable Input voltage: 220V± 20% or 380V± 20% Output voltage: 0-150V/0-300V The rate of voltage regulation supported: Less than or equal to ± 1% Wave distortion: Less than or equal to 1% Protective device: Having had year, excessive load, input voltage shortage, pass the high temperature, overvoltage, short circuit protection Variable frequency power supply / exchange power supply YF/SPS-3600 single-phase heavy-duty serial three phases import single-phasely and export the products (10VA-200KVA) Common characteristic Input the frequency: 50Hz, 60Hz or 400Hz. Output voltage: 0~300VAC. Output frequency: 40.0~499.9Hz finger type. The voltage, frequency, electric current, power meter adopt 4 digits LED to reveal, simple, readability, high analyzed. Voltage (V) , frequency (Hz) , electric current (A) , power (W) , 4 Windowses, gauge, reveal, not need to switch over at the same time. there is no radiated interference, it is small to includes the harmonic composition and and through special-purpose processing, do not interfere. Pure, stable sine wave High capacity, small volume, high reliability with low noise. Offer standard voltage, frequency, various electric equipment products of simulation to the countries all over the world. Voltage, frequency, various electric equipment products of mock test. Overload capacity is strong. The electric current can bear 3 times of rated current in the twinkling of an eye. have had voltage, excess current, passed high-temperature protection and warning absorption. Suitable for the resistance type, capacitive, inductive character and others are not the use of linear load. Employ the place Research and develop, make and Quality Assurance test, voltage, frequency, various electric equipment products of mock test. Aviation, vessel, power simulation National defence, military affairs, research unit