The following article presents a very simple low current 220 V mains operated transformerless power supply circuit using an inexpensive MJE13005 transistor and few other passive electronic components.
As can be witnessed in the given circuit diagram, the design is extremely straightforward.
How it Works
Transistor T1, which is a high voltage NPN transistor MJE13005 forms the main active component in the circuit.
Rest of the components are positioned just for supporting the conduction of T1 and for the required stabilization.
The circuit can be understood with the following points:
Mains input is fed across D2 and the negative line of the circuit.
D2 rectifies the mains AC, while C1 filters to some reasonable levels.
R1 drops the current to tolerable limits in order to provide the required base bias for T1.
C2 provides further filtration to the voltage generated after R1.
D1 clamps the base voltage at the base of T1 to 24V, such that the maximum output voltage can never exceed this limit.
A mirror voltage which is always equal to the zener value is generated at the output, however the presence of R2 enables the response to become variable.
The adjustments made through R2 effectively varies the zener voltage right from zero to the maximum value, that is up to 24V.
Thus the obtained output becomes variable from zero to 24V.
However since the voltage is acquired across the emitter/ ground of the transistor, the current gets restricted to very modest levels, at 25mA to be precise.
The zener voltage though may be increased to any desired limits.
WARNING: THE WHOLE CIRCUIT IS NOT ISOLATED FROM MAINS AC, THEREFORE IS EXTREMELY DANGEROUS TO TOUCH WHILE IT'S UNCOVERED, AND POWERED CONDITION. MAKE SURE YOU HAVE MAINTAINED ALL THE NECESSARY PRECAUTIONS WHILE HANDLING THIS CIRCUIT.
Parts List
R1 = 100k
R2 = 10K POT
C1 = 4.7uF/300V
C2 = 10uF/100v
C3,C4 = 100uF/30V
D1 = 24V, 1WATT, ZENER DIODE
D2 = 1N4007
T1 = MJE13005
Comments
Hello,
I'm sure you know this is very late asking a question regarding your design. Hopefully you will read this.
I see your parts list, but can you give values for the wattage for…. R1. Will this need adjustment in case of modifying the output, I've, if output is required at 12v, will RI wattage be different?
Many thanks
Rich
Hello, R1 is 1/4 watt rated..it's not recommended to adjust its value because lowering it can damage the transistor.
Hello,
One question regarding your schematic : would it work with only the phase 220VAC line and no neutral.
I'm working on a power supply for a small radio module to controle light switch. behind the light switch I don't have the neutral line.
hello, you can use an "earthing" line as the neutral, for example it could be your bathroom water tap line…
It's D1, I'll correct it in the article soon
Which diode is wrong???
Is it the 24V zener or the general purpose 1N4007 ???
try a 400V capacitor for C1, or simply don't use anything, eliminate C1 and first try the circuit without it.
please translate in english
Bro can I use this pcb with smd led? If yes then how much number of minimum qnd maximum led I cn use..,
Bro I won't recommended this circuit for SMD because SMDs are costly and we require foolproof design, so better go for a 12V SMPS adapter available readymade.
hi sir im a electronic hobbiest
can i use this circuit to power 100 led lights
Hi Vikram, use the following circuit, the above will not work:
https://www.homemade-circuits.com/2012/03/how-to-make-simplest-1-watt-led-driver.html
put all the LEDs in series and join it with the output of this circuit
Dear Sir,
Do you have any circuits high current application above my spec
Thanks & Regards
S.Bharanidaran
Dear Bharani,
According to me an SMPS would be the correct option choice for driving a high watt LED.
you can easily procure a readymade 24/1amp smps unit ad power your LED through
it….smps amp is not crucial as long as the voltage does not exceed above the led specs.
Dear Sir,
The above circuit use in 23v/300ma Led light(7watts)
Thanks & Regards
S.Bharanidaran
Dear Bharani,
No, it's not suitable for high current applications.
T1 is the main component which does the required voltage dropping.
sir,
Do you have any circuit which provide 12v 100ma current…..
Avik, you can use the above circuit and add an overboard transistor across the existing mje13005 for boosting current to the required levels.
I'll try to update it soon here.
What if i inverse the polarity of capacitors in this ckt ? They will explode right sir??
about 500-1A cause i will use it to drive a TDA 2822M and charge two smartphones
For charging batteries you will have to employ an smps circuit, other forms won't be safe as these may not be isolated from mains AC and also not capable of producing higher current outputs.
hi
can you help me 5v-12v transformer-less power supply circuit
hi, what's your current requirement? please specify the current requirement.
sorry 1 amp won't be possible.
Dear Aruna,
According to me there's no possibility of a surge in this circuit.
can you please upload high power led driver circuit for 400w led.
you can use the following circuit:
https://www.homemade-circuits.com/2011/12/make-hundred-watt-led-floodlight.html
just replace the components by calculating them with the given formula.
You will need an external smps to drive the above circuit