Saturday, 22 March 2014

How to make Transformerless or Electronic Power Supply/Driver

How to Make Transformerless 12Volt 1 Ampere or 2 ampere or more amperage compact DC electronic Power Supply or Driver/Charger.


Today we are going to learn how to design and make the Cheapest and Smallest Transformerless electronic Power Supply or capacitive power supply 12v 1a or 2a according to our requirement. Actually there are many Power supplies available in the market but most of them are transformer/smps based and are very Big, Bulky, ugly, costly and have very complex circuitary to understand by a complete newbie.

So, lets get started to learn the design procedure so that we will be able to make the desired electronic power supply onward.

The biggest advantage of this explained circuit is that it is independent of input voltages fluctuations to a great extent

Here, we assume the input power source used here is 220V AC OR 110V AC 50~60Hz from home wall socket directly.


C1= 400V, 1395K Capacitor or (Connect three 400v, 475k caramic capacitor in parallel or three 2uf/400v caramic capacitor) (Note if the mains current is 220v AC 50-60Hz if mains is 110v AC then use 250v/1395k).

[The above circuit is Verified and Tested circuit by me and works great, so make it, save money & enjoy.]


In above circuit, R1 is actually doing nothing, but serve's the purpose of Bleeder Resistance, means it discharges the Charge stored in C1 gradually when the circuit is not in use( it may takes time between 1 to 15 sec according to its value and amount of charge stored).

This power supply is best suited for Capacitive loads like charging the battery, LED Drivers or any capacitive load...

So, By by reading the below post you guys will be able to design and make the power supply of any current rating and voltage rating according to your requirement. So please be focused and attentive to understand the technical specifications.

[Instruction: Above project deals with mains AC current & not isolated from AC mains, So be careful and work always under the guidance of any elder if you are a complete newbie. Please always remember to keep your one hand in pocket whenever working with any live circuit so that in case the current wont pass through your heart just for safety].


In my next post i m going to post a circuit of 12V 5 ampere transformer less electronic switch mode power supply(or SMPS based) or Driver.

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Today we are going learn a new type of circuit generally known RC circuit or capacitive power supply, which is the simplest and Cheapest circuit you will find ever.

I have created this Circuit during my research on how to increasing the power output of electronic or transformer less power supply for capacitive loads.

So now the question arises here is that - How to make this great and easy piece of Transformerless Electronic Power Supply or LED driver circuit at home.

C1= 400V, 1395K Capacitor or (Connect three 400v/475k or two 2uF/400V capacitor in parallel for 1.2Ampere or higher capacitance for higher current according to the calculations explained below).

R1= 10M ohm or 1M ohm 1watt resistor.

D1-D4= IN5408 (4 DIODES)( just choose diodes which have double ratig for our curent requirement for e.g. for 2 amp choose diode of rating 4 amp...)

R2= 10 ohm 1 or 2 watt.( 2 watt will be better for heat handling or dissipation)

C2= 1000uF(micro faraday) ,50 v ( 2 in number if you finds the output is fluctuating, connect them in parallel for better filtering of ripples produced due to rectification of AC mains current).

z1= zener of 15v to prevent any voltage fluctuations caused due to input voltage fluctuation to regulate our DC output to maximum of 15 volt max in extreme case.

{note: you must add a 10M or 1M ohm as a bleeder resistance parallel to C2 for Discharging the charge stored in C2 otherwise you may get a high current shock or surge current dur to charge stored in the capacitor if this charge is not discharged when circuit is not in operation it is going to remain for very long time and someone may get the shock. In later posts we will learn the techenique to remove any surge current by incorporating a crowbar circuit at the output. So simply to understand better this circuit and make it simple simply connect a higher value capacitor across capacitor C1.}

{Do not touch any terminals with bare hands even the Driver is Unplugged. First discharge the C1 and C2 by shorting the input and output terminal together. there will be spark generated while doing this this means charge stored is discharged completely by you now. Only after that you should touch any terminal, or leave for some time before touching the terminals so that bleeder resistance work for you to discharge the charge stored in capacitor C1.}


If we use 2uF/400V(because it is readily available in the market) THEN :

the capacitive reactance offered by capacitor(2uF/400V) connected at mains supply is:
x= 1/(2*pi*f*c) where pi is 22/7, and f is the frequency of mains supply eg 50Hz or 60Hz
now reactance or impidence ( or simply resistance) of whole ckt is = sqrt(R+x) where R is the resistance or load and wires all together attached in circuit and sqrt means squareroot of (R+X)
now out put current i=(v/z) where v= mains voltage 220v or 111v
So you can now calculate the capacitance of circuit according to the required current.

If you want to increase the output current just simply increases the capacitance value of C1 or just by Adding more C1 together in parallel if you are unable to find the appropriate value capacitor in market.

The C2 here only used as a filter to reduce the ripples in the output waveform.( it acts as filter to smoothen the output DC desired.)

Z1 is zener to protect the appliances from overvoltages.

If you want to decrease the voltage rating just use appropriate zener diode

If you wanted to increase the voltage rating of the circuit to double just use doubler circuit to double the voltage but the catch is that the current will become half and frequency become twice means 120Hz. so according to your requirement just increase the output DC current by simply adding high capacitance capacitor or add more C1 in parallel if you need high output DC voltage

For capacitance C1 related calculation problems or any problem regarding this explained circuit please reply in comment section and i will be happy to help by reply ASAP.

If you find above circuit interesting or useful please share it will be our reward from your side.

 Thank you for Reading.

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