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Transformerless power supply circuit principle

2015-03-21 21:01  
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This article describes a transformerless power supply circuit. The circuit is relatively simple, it is easy to grasp. Here you'll read the following diagram combine text bar. This circuit can be set up very small and can supply small current small projects. The main downfall is that it is not isolated from the supply of AC line and can only supply a small current. The value of C1 can be increased to increase the number of the current supply circuit. The values ??shown, the circuit can provide 15 Ma. Remember to increase the size of C2 also. A different value can be used to increase or reduce the required D1 voltage. Please note that this circuit is not isolated from 120 vac. Therefore, the circuit must be treated with caution and encosed at all times. Does not work on the circuit (or any other circuit connected) when it is inserted. You might want to add a resisor series C1 limit the current if the circuit is inserted and the power at its full voltage. If you are running from a 220 VAC circuit, and then use a capacitor rated at greater than 400 v to C1. If you want to cut off the AC line, you can connect a small isolation transformer input circuit. Small 600 ohm: 600 ohm audio transformers work well. If you want a thorough understanding of the principles of the circuit, I suggest you can go to find out the important components of the circuit: 1N4741 , etc.. 


Schematic for Transformerless Power Supply


PartTotal Qty.DescriptionSubstitutions
C110.39uF 250V Capacitor 
C21220uF 25V Electrolytic Capacitor 
D111N4741 11V Zener Diode (See Notes) 
BR111 Amp 200V Bridge Rectifier 
MISC1Line Cord, Board, Wire, Case



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