Fixed Voltage Power Supply

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The fixed voltage power supply is useful in applications where an adjustable output is not required. This supply is simple, but very flexable as the voltage it outputs is dependant only on the regulator and transformer you choose. The maximum output current is 1.5A.

Schematic

Parts

Part	Total Qty.	Description	Substitutions
C1	1	2200uF 35V Electrolytic Capacitor
C2, C4	2	0.1uF Ceramic Disc Capacitor
C3	1	10uF 35V Electrolytic Capacitor
D1, D2	2	1N4007 Silicon Diode
BR1	1	2A 30V Bridge Rectifier
U1	1	Regulator (See Notes)
T1	1	Transformer (See Notes)
S1	1	SPST 2 Amp Switch
F1	1	2A 250V Fuse and Holder
MISC	1	Heatsink For U1, Line Cord, Case, Wire

Notes

Since this project operates from 120 (or 220, or 240, etc.) volts AC, it MUST be built inside a case.

U1 will reauire a heatsink.

You will need to choose T1 and U1 to match the voltage you want. Use the table below as a reference.

Output Voltage	T1	U1
5V	6V, 1.5A	7805
6V	6V, 1.5A	7806
9V	12V, 1.5A	7809
12V	12V, 1.5A	7812
15V	24V, 1.5A	7815
18V	24V, 1.5A	7818

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Comments

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anonymous Fixed Voltage Power Supply Thursday, September 26, 2013 10:53:29 AM

shouldn't the T1 be at least 2V more than the required voltage?

CHARLIE Fixed Voltage Power Supply Sunday, June 03, 2012 5:04:31 PM

how to generate a one volt power supply from an main ac supply.

Greg Taylor Fixed Voltage Power Supply Tuesday, March 06, 2012 9:53:13 AM

I am involved in a senior project that requires me to build a 6V 1.5A power supply. How can I determine what the values I need for the Fixed Voltage Power Supply schematic that is provided from your website? Your help is very much needed. Thanks.

anonymous Fixed Voltage Power Supply Wednesday, February 01, 2012 4:58:05 AM

The 1/2/3 are the pins on the LM78xx. I have a question though. Since I'm going for 5v out, I imagine that I could replace the LM78xx with the R-785.0-1.0 from RECOM? Better efficiency but would only have 1A out, for me that's fine as it's only to power USB type devices.

anonymous Fixed Voltage Power Supply Tuesday, January 10, 2012 10:33:50 AM

can u please tell me why 3 & 2 is written in U1

arslan Fixed Voltage Power Supply Saturday, December 03, 2011 4:29:18 AM

its very easy ,use ( LM7805 ) to get 5v DC power supply

anonymous Fixed Voltage Power Supply Tuesday, October 05, 2010 11:51:28 PM

Should the Switch (S1) not be on the Positive / Live side before the transformer?

yuki Fixed Voltage Power Supply Saturday, August 28, 2010 9:35:00 PM

what is the purpose of D1, D2, C2, C3, and C4? And, why you didn't include resistor in the filter and for the load? thanks... hope you answer my questions ASAP...thanks again

Sandro Pace Fixed Voltage Power Supply Thursday, August 05, 2010 8:01:21 AM

Hi, I would like to build a power supply that can give out 24V DC at 5A from 240V AC. What parts in this circuit do I need to change to achieve this. Thanks.

ARSALAN AKRAM variable power supply Saturday, January 02, 2010 10:57:21 AM

ASSALAM o ALAIKUM! sir i want the circuit which regulate from 1.2 to 30 but i want that circuit having transformer whose AC input is 220 volt i have seen your circuits in your circuits AC input in the transformer is 120. plz give me the circuit as soon as possible i shall be very thank ful to u for this act of kindness

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anonymous	Fixed Voltage Power Supply	Thursday, September 26, 2013 10:53:29 AM
shouldn't the T1 be at least 2V more than the required voltage?
CHARLIE	Fixed Voltage Power Supply	Sunday, June 03, 2012 5:04:31 PM
how to generate a one volt power supply from an main ac supply.
Greg Taylor	Fixed Voltage Power Supply	Tuesday, March 06, 2012 9:53:13 AM
I am involved in a senior project that requires me to build a 6V 1.5A power supply. How can I determine what the values I need for the Fixed Voltage Power Supply schematic that is provided from your website? Your help is very much needed. Thanks.
anonymous	Fixed Voltage Power Supply	Wednesday, February 01, 2012 4:58:05 AM
The 1/2/3 are the pins on the LM78xx. I have a question though. Since I'm going for 5v out, I imagine that I could replace the LM78xx with the R-785.0-1.0 from RECOM? Better efficiency but would only have 1A out, for me that's fine as it's only to power USB type devices.
anonymous	Fixed Voltage Power Supply	Tuesday, January 10, 2012 10:33:50 AM
can u please tell me why 3 & 2 is written in U1
arslan	Fixed Voltage Power Supply	Saturday, December 03, 2011 4:29:18 AM
its very easy ,use ( LM7805 ) to get 5v DC power supply
anonymous	Fixed Voltage Power Supply	Tuesday, October 05, 2010 11:51:28 PM
Should the Switch (S1) not be on the Positive / Live side before the transformer?
yuki	Fixed Voltage Power Supply	Saturday, August 28, 2010 9:35:00 PM
what is the purpose of D1, D2, C2, C3, and C4? And, why you didn't include resistor in the filter and for the load? thanks... hope you answer my questions ASAP...thanks again
Sandro Pace	Fixed Voltage Power Supply	Thursday, August 05, 2010 8:01:21 AM
Hi, I would like to build a power supply that can give out 24V DC at 5A from 240V AC. What parts in this circuit do I need to change to achieve this. Thanks.
ARSALAN AKRAM	variable power supply	Saturday, January 02, 2010 10:57:21 AM
ASSALAM o ALAIKUM! sir i want the circuit which regulate from 1.2 to 30 but i want that circuit having transformer whose AC input is 220 volt i have seen your circuits in your circuits AC input in the transformer is 120. plz give me the circuit as soon as possible i shall be very thank ful to u for this act of kindness