24V DC miniature motor on AC 220V

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If I allowed to use transformer sure I won't use this matter....

this morning I tried 0.47uF 350V with the 5w1k2 ceramic resistor, the cap blow after 1 minute.........
 

Wrong CAP, mate ..
Use a capacitor that is rated for ≥250V AC !!!

Regards,
IanP
 

o ic.....I got 0.1uF 275VAC Capacitor, suitable or not?

Added after 37 seconds:

o ic.....I got 0.1uF 275VAC Capacitor, suitable or not?
will this circuit give around 100mA of current?
 

This one is suitable, but for 100mA you will need to connect several ( ≈ 14 x 0.1µF) caps in parallel ..

Regards,
IanP
 

1. The Circuit That IanP supplied is wonderful, But I guess you should replace ZD1 and ZD2 by 24V zener diodes.

2. you can replace the pre-rectifier stage in IanP circuit by a transformer as roykyn suggested. and this will simplify the implementation but it will make it more expensive.

3. Don't Use SCRs (Thyristors) as Jepeto suggested, the switching of these devices is very complicated. And you will have to build a time wasting electronic circuit for firing the gates. Moreover , you will meet many grounding problems.

Regards
 

You should first know what current do you need at 24V DC and then calculate series capacitor.
 

I need 50mA on 24V DC,how to calculate?do I need to change the series resistor also if I change the series capacitor?
 

anyone got any ideal? I need aroung 50mA~100mA.
Ianp suggested connect 14x0.1uf caps.but I dont hav the much spacing.......
 

I built this cct previously to power LED from 240v mains. You can try it to power the motor but you must know exactly the motor rating.
If the 470R resistor burn out then yr motor must draw large current than what you mentined.
Again putting ALL these in a tight place is not a good idea - use it at yr own risk!
 

Dear dindeds,
how much current yr circuit can supply?


Regards

Added after 5 hours 2 minutes:

how many current can this circuit supply?
 

Dear Ianp,
I use the circuit U posted recently on a 12V DC multivibrator circuit with 10mA, the circuit flash very fast, how do I overcome this problem?

Regards
 

About 100mA max. You can lower the resistance to get more current at the expense of more heat! That's one of the reason this circuit not suitable in tight spaces.
 

assuming we get 100mA when Using 470R,if I use 680R how many current I get?Do i need to reduce the capacitor value also?


Regards

Added after 1 hours 42 minutes:

Dear Dindeds,
I tried yr circuit, it only giv 10mA, my DC motor can't run.....even I tried a 30mA LEDs multivibrator circuit it result in low brightness......I get the current reading from the multivibrator,its only 10mA after I added 220uF e-cap parallel to the output.......any ideals?
 

Try using a larger AC capacitor (1uF) or put another 0.47uF in parallel with C1 first, if still not enough current lower the resistor value in small increment (390R or 330R). Increasing the resistor value lowers the current. Lowering the value too low will fry the Zener diode.
 

Am now using 0.68uF & 330R,only get 12.5mA.....stil far away from my terget=100mA

Added after 16 minutes:

Can this circuit provide more current?
 

This circuit will provide enough current to blow up D1 and C2 and maybe diodes too.
 

That is a full-wave rectifier, you'll get 300V+ on the o/p !
You can try replacing R1 with a fuse and insert a 3.3K 5W resistor before the Zener diode. It may get quite hot!
 

pls help guys,I need 100mA transformerless power supply......
 

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