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| Author | Views | Views Today | Rank | Comments |
| 142,015 | 5 | |
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| I have received a few emails asking for a transformerless power supply. Here is such a supply. This supply uses no heavy step down transformer and has an extremely low parts count. The circuit can be built very small and can supply small currents for small projects. The major downfall of this supply is that it is not isolated from the AC line and can only supply small currents. |
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| i want to ask anybody if the supply from this power supply can use to halogen bulb 100w 12volts? if can used this supply on this bulb? thank you.. | ||
| i have already made this transformer less power supply, but i have lot of question about this. all of them have been asked by other friends here. i also want to answer of these question, tell what i have to do find the answer. | ||
| C1 is being used as a current limit and voltage dropping device. The reactance of 0.39 uF capacitor at 60 Hz is 6800 ohms, but it uses no power and does not heat up like a resistor would. The output of this supply will vary widely as more current is drawn from the output, as more voltage will be dropped across C1. To calculate the output voltage, the load current must be known. | ||
| NY - To use zener diodes for a 15 volt supply, you should place your resistor between C2 and your zener cathode, then take the load from across the zener. You may appear to have a square wave output if you connect the scope ground to the power supply negative output and use the probe on the positive output. This is because the scope ground is at AC Line Neutral potential, while the negative terminal output of your power supply is not. When you connect the scope ground to the negative terminal, you are shorting out a pair of the rectifier diodes. To properly observe the output requires that you use a dual trace scope set for differential mode (B-A), using ch2 at the neg output and ch1 at the positive output and the scope common connected to the AC Neutral wire. Set both channels for 5 V/div direct coupling. | ||
| I build the transformerless power supply, I added a resistor (100 ohms) in series with C1 (1.47 microF), the bridge rectifier (1N4007 x4), Zener diode D1 ( 3 Zener diodes in series to get 15V) and C2 470microF. I got a squarewave of 15V, could you please advise? | ||
| You have a wonderful site running. I give you that. My problem is that I live in Nigeria and most of the components in your design cannot be found in this part of the world. I will like you to use components that are easily fetched. Thanks | ||
| Transformerless power supplies are a VERY dangerous and bad idea. Transformers are far safer, and infinitely less expensive than the costs for a funeral. | ||
| i just wanna know what should i used or what can i replace for c1 coz that value is not available in our place... please please | ||
| iam a begginer here can i ask what kind of capacitor in c1 should i use? | ||
| Can I use this trnsformless supply on 220 V AC? | ||
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