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Can someone please explain parts of this diagram

wedagedara

Feb 9, 2012
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Can someone please explain parts of this diagram

VISIT HERE

Please tell me what is:
R1:
R2:
R3:
C1:
C2:
And what are the four diodes used(in4xxx)
My electronic knowledge is not so good. I just need to repair my lamp.
Thanks a lot
 

Harald Kapp

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The four diodes are a bridge rectifier. Input pins 1 and 3 are AC, output pins 2 and 4 are DC.
R1, C1 and R3 are current limiters. C1 operates on the AC side. The value 334 means 330nF. At 50 Hz this is equivalent to ~10kOhm. A capacitor is used instead of a resistor because it has lower power loss due to the phase shift between current and voltage.
R2 is for safety reasons. It discharges C1 when the lamp is turned off.
C2 is a smoothing capacitor. The DC voltage after the rectifier still has a large AC voltage superimposed which is reduced by C2.
 

wedagedara

Feb 9, 2012
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The four diodes are a bridge rectifier. Input pins 1 and 3 are AC, output pins 2 and 4 are DC.
R1, C1 and R3 are current limiters. C1 operates on the AC side. The value 334 means 330nF. At 50 Hz this is equivalent to ~10kOhm. A capacitor is used instead of a resistor because it has lower power loss due to the phase shift between current and voltage.
R2 is for safety reasons. It discharges C1 when the lamp is turned off.
C2 is a smoothing capacitor. The DC voltage after the rectifier still has a large AC voltage superimposed which is reduced by C2.

No, i didn't meant to explain their works. I just asked what are the values of them(Eg: 10K, 33uF, etc). So it useful to buy them from a shop. The diagram is not clear to identify them,
So please tell me what are R1, R2, R3, C1 and C2.
Thanks
 

CocaCola

Apr 7, 2012
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The diagram is not clear to identify them

Sure it is...

attachment.php
 

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(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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resistors are in ohms. C1 is 0.33uF and must be mains rated.
 

CocaCola

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resistors are in ohms. C1 is 0.33uF and must be mains rated.

Generally recommended that C1 be 1.5-2.0 times or better than the mains rated in this application... This is to help compensate for transients in the mains supply...
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Generally recommended

When I say "mains rated" I mean that the capacitor is rated to be placed across the mains.

And my meaning was clearly not clear. So, for the benefit of wedegedara:

The lowest of these is Class X (there are also X1 and X2 with higher ratings).

See here.
 
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