power supply cont.. - Electronic Circuits Projects Diagrams Free

sigma · 8th March 2003, 08:04 PM

hi again
here's what i came up with
it's some sort of i'mprovement over
my first ckt.
it's working and all but
the voltages are sligthly off
around .5-.7v
:?
any ideas what i could do to
fix this tnx

**kinjalgp** · 8th March 2003, 08:18 PM

Whay have you used those 2W resistors? I don't think there is any use of them in the circuit except you wish to limit some curent. But these ICs already have a thermal shut-down which will switch-off the output current flow as soon as its temperature goes beyond a preset value.

bogdanfirst · 8th March 2003, 08:35 PM

it seems that you have a pin from the second rectifier unconnected. is it just a graphic error?
and, yes, you dont need the 2W resistors, and if you stil use them you will have more power disipated at the maximum current drawn from the suply.

bogdanfirst · 8th March 2003, 08:54 PM

here are basicly 2 ways that i would make it.

sigma · 8th March 2003, 09:11 PM

both ideas are good and i will look into improvements but could someone
tell me how to stabilize the voltage.

Sebi · 8th March 2003, 11:41 PM

And this is better, because the dissipation is lower on 7805. When You need for 12V only 100...200 mA, connec it to lower input voltage.
7805, 7812, and LM317 outputs voltage stabilised.

bogdanfirst · 9th March 2003, 10:13 AM

yes, an even more improoved idea.

sigma · 10th March 2003, 04:11 PM

tnx for the ckt. sebi
will make the modifications to my ckt.
Oh and to answer your question bogdadnfirst
that unconnected pin is not a typo it's just unneccesary.
tnx again guys.

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8th March 2003, 08:18 PM	(permalink)
kinjalgp	Whay have you used those 2W resistors? I don't think there is any use of them in the circuit except you wish to limit some curent. But these ICs already have a thermal shut-down which will switch-off the output current flow as soon as its temperature goes beyond a preset value. __________________ "There is no way to peace, peace is the way!"

8th March 2003, 08:35 PM	(permalink)
bogdanfirst	it seems that you have a pin from the second rectifier unconnected. is it just a graphic error? and, yes, you dont need the 2W resistors, and if you stil use them you will have more power disipated at the maximum current drawn from the suply.

8th March 2003, 09:11 PM	(permalink)
sigma	both ideas are good and i will look into improvements but could someone tell me how to stabilize the voltage.

9th March 2003, 10:13 AM	(permalink)
bogdanfirst	yes, an even more improoved idea.

10th March 2003, 04:11 PM	(permalink)
sigma	tnx for the ckt. sebi will make the modifications to my ckt. Oh and to answer your question bogdadnfirst that unconnected pin is not a typo it's just unneccesary. tnx again guys.