Chip amp power supply- a beginners guide

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AndrewT

R.I.P.
Joined 2004
AndrewT said:
Hi,
the 300VA transformer can be specified as 300/ [25+25] = 6Aac.
the 225VA transformer can be specified as 225 / [25+25] = 4.5Aac.
the 170VA transformer can be specified as 170 / [25+25] = 3.4Aac.
Click to expand...


neeraj said:
Hi,Andrew T,
The question is say i m using 170 Va trafo for single LM 3886
What is the output of transformer in amp.

0-25=1.7 Amp Or 3.4amp?
25-0-25=3.4 amp or 6.8 amp?
Click to expand...
170VA 25+25Vac = 3.4Aac
170VA 25Vac = 6.8Aac.
Use the calculator program built into MSwindows.
 
N

neeraj

Member
Joined 2005
neeraj said:
Hi,Andrew T,
The question is say i m using 170 Va trafo for single LM 3886
What is the output of transformer in amp.

0-25=1.7 Amp Or 3.4amp?
25-0-25=3.4 amp or 6.8 amp?

:) :)
With best regards
Click to expand...


AndrewT said:



170VA 25+25Vac = 3.4Aac
170VA 25Vac = 6.8Aac.
Use the calculator program built into MSwindows.
Click to expand...

Dear Andrew T,
I have used the calculator
:)

But a bit confused :( ,

thanks for your help

with best regards
 
Professor

Professor

Member
Joined 2005
mymegahobby.jimdo.com
Hi all!
Maybe someone need, very interesting scheme of softstart.
 

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P

pacificblue

Member
Joined 2008
If you mean with fixing that you need a switch instead of a button, then no. A latching relay toggles between its two states by means of a ratchet mechanism each time the coil is exited. You often find them in building installations, where lights must be switched on and off from many places, e. g. in an aisle, and where this type is used. Other styles are available from many manufacturers.
There are two types of latching relays. For use with a single pushbutton, the single coil type is the right choice. The type with separate coils for setting and resetting requires two pushbuttons.
 
Professor

Professor

Member
Joined 2005
mymegahobby.jimdo.com
pacificblue said:
If you mean with fixing that you need a switch instead of a button, then no. A latching relay toggles between its two states by means of a ratchet mechanism each time the coil is exited. You often find them in building installations, where lights must be switched on and off from many places, e. g. in an aisle, and where this type is used. Other styles are available from many manufacturers.
There are two types of latching relays. For use with a single pushbutton, the single coil type is the right choice. The type with separate coils for setting and resetting requires two pushbuttons.
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Latching relay nice thing but I already used my scheme =)
 

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raypalmer

raypalmer

Member
Joined 2008
question...

My chipamp.com boards are all done. The PSU measured fine, then I attached the amplifier board. Now it blows fuses. I stuck a 10amp fuse in to see what was happening, the traffo heated up in a few seconds, the inside two diodes on the bridge heated up fantastically hot and the outside two not so much. There was a slight hum coming off the board..... Help... Everything looks to be wired correctly.
 
raypalmer

raypalmer

Member
Joined 2008
LucasAdamson said:
Disconnect the amp again to see if the power supply is still as it was?

Check for too much solder causing short circuits across traces on the PCB?

Check the diodes are in the right way around (a common problem I have read).
Click to expand...

Well I disconnected the V and PG's and the PSU didn't smoke out on me. So that rules out the error being on the psu amirite?

I guess I'll peel off the amp board tomorrow and give it a good eyeballing...

My diodes will be fine right? They got super-crazy hot when I ran it with the 10amp fuse but it seems ok now?
 
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