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

Numlock Fixed Voltage Power Supply Monday, March 30, 2009 4:56:20 AM

Hello, I've been building grow light panels using cement mixing tubs from a home center and high output LEDs. The combination of 1 blue (465nm) to every 3 red (650nm) works very well. The LEDs that I use are 10,000mcd with iF of 30ma at 3.6vF. To this point I have been buying used 36VDC golf cart battery charging transformers. These chargers average 36VDC with spikes up to 36.2VDC so I run multiple series of 10 LEDs with 6.8Ohm 1/4 watt resistors per series. I use a grid of 17 x 21 with 3/4" on center. This leaves 3 LEDs unaccounted for so I place them on the panel enclosure as 'decorations'. My problem is that all of this depends on golf cart battery chargers remaining available and inexpensive. I find that it is getting harder and harder to find then. I think that most carts are now operating at 24VDC or 48VDC and that 36VDC is an obsolete design. That just means that I need to build my own. The design pulls 1,080ma of current and draws 39,100.32mw of output power. I have looked at 18VDC but an ideal design pulls 2,160ma of current at 18VDC. 2A is not quite enough and 5A transformers are ridiculously expensive. Is there a design out there for a 110/120VAC to 36VDC power supply? Thank you

Bablu 7-segment display-com.anode type. Wednesday, January 14, 2009 10:18:47 AM

I've Constructed a CKT Of 7-segment display anode type which uses conman anode type display.I've obtained the output which mean display shows digit from'0-9' but whats happened the no. is appearing randomly.please send me a solution on it

Mir Qadeer Ali Fixed Voltage Power Supply Saturday, August 23, 2008 3:40:12 PM

i have constructed 230v ac to 9v dc, by using 12v transformer and 7809 regulator, now am in need of 6v dc, what modification i should from the above, or i have to built seperate circuit by using 6v transformer and 7806 regulator, let me know by my email as soon as possible , thank you

Graham Fixed Voltage Power Supply Wednesday, May 21, 2008 1:01:12 AM

Hi, Please help me I need to step down DC voltage from +/-13 -14.4V to 11.5 - 11.9V @ 3A DC can you help?

Stram Fixed Voltage Power Supply Tuesday, April 29, 2008 11:22:24 AM

a friend from U.S.A. gave me an HP Printer/Scanner without a power supply, since i am fond electronics assembling, i want to assemble a 24V greater than1.5A fixed regulator. Please help and provide me Thank you very much, STRAMM

Maxspower Fixed Voltage Power Supply Tuesday, April 15, 2008 4:37:08 PM

"What si the prupose of the fuse and capacitors" . . . love it! LOL

sammaking Fixed Voltage Power Supply Tuesday, February 26, 2008 5:31:39 AM

please help me out with the circuit diagram of a variable dc output (-12,+12 & +5v) power supply of 110v ac input

eliya Fixed Voltage Power Supply Tuesday, February 19, 2008 12:16:11 AM

how about if the output voltage is 25 Vdc and the maximum output current is 5 Ampere? how the circuit going to be?this power supply will use the source from 240 Vac.can u please help me on this problem.reply to my email.thank you

mebrahtu Fixed Voltage Power Supply Friday, January 04, 2008 1:43:54 AM

In the above citcuit u1 means transistor please explane

Joe Soup Fixed Voltage Power Supply Tuesday, January 01, 2008 1:10:54 AM

What is the requirement on the voltage capacity of the .1uf disc capacitors? I looked at radio shack and the only ones they have listed are 50v. Would this be too much, since the other voltages seem to be 35v?

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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

Numlock	Fixed Voltage Power Supply	Monday, March 30, 2009 4:56:20 AM
Hello, I've been building grow light panels using cement mixing tubs from a home center and high output LEDs. The combination of 1 blue (465nm) to every 3 red (650nm) works very well. The LEDs that I use are 10,000mcd with iF of 30ma at 3.6vF. To this point I have been buying used 36VDC golf cart battery charging transformers. These chargers average 36VDC with spikes up to 36.2VDC so I run multiple series of 10 LEDs with 6.8Ohm 1/4 watt resistors per series. I use a grid of 17 x 21 with 3/4" on center. This leaves 3 LEDs unaccounted for so I place them on the panel enclosure as 'decorations'. My problem is that all of this depends on golf cart battery chargers remaining available and inexpensive. I find that it is getting harder and harder to find then. I think that most carts are now operating at 24VDC or 48VDC and that 36VDC is an obsolete design. That just means that I need to build my own. The design pulls 1,080ma of current and draws 39,100.32mw of output power. I have looked at 18VDC but an ideal design pulls 2,160ma of current at 18VDC. 2A is not quite enough and 5A transformers are ridiculously expensive. Is there a design out there for a 110/120VAC to 36VDC power supply? Thank you
Bablu	7-segment display-com.anode type.	Wednesday, January 14, 2009 10:18:47 AM
I've Constructed a CKT Of 7-segment display anode type which uses conman anode type display.I've obtained the output which mean display shows digit from'0-9' but whats happened the no. is appearing randomly.please send me a solution on it
Mir Qadeer Ali	Fixed Voltage Power Supply	Saturday, August 23, 2008 3:40:12 PM
i have constructed 230v ac to 9v dc, by using 12v transformer and 7809 regulator, now am in need of 6v dc, what modification i should from the above, or i have to built seperate circuit by using 6v transformer and 7806 regulator, let me know by my email as soon as possible , thank you
Graham	Fixed Voltage Power Supply	Wednesday, May 21, 2008 1:01:12 AM
Hi, Please help me I need to step down DC voltage from +/-13 -14.4V to 11.5 - 11.9V @ 3A DC can you help?
Stram	Fixed Voltage Power Supply	Tuesday, April 29, 2008 11:22:24 AM
a friend from U.S.A. gave me an HP Printer/Scanner without a power supply, since i am fond electronics assembling, i want to assemble a 24V greater than1.5A fixed regulator. Please help and provide me Thank you very much, STRAMM
Maxspower	Fixed Voltage Power Supply	Tuesday, April 15, 2008 4:37:08 PM
"What si the prupose of the fuse and capacitors" . . . love it! LOL
sammaking	Fixed Voltage Power Supply	Tuesday, February 26, 2008 5:31:39 AM
please help me out with the circuit diagram of a variable dc output (-12,+12 & +5v) power supply of 110v ac input
eliya	Fixed Voltage Power Supply	Tuesday, February 19, 2008 12:16:11 AM
how about if the output voltage is 25 Vdc and the maximum output current is 5 Ampere? how the circuit going to be?this power supply will use the source from 240 Vac.can u please help me on this problem.reply to my email.thank you
mebrahtu	Fixed Voltage Power Supply	Friday, January 04, 2008 1:43:54 AM
In the above citcuit u1 means transistor please explane
Joe Soup	Fixed Voltage Power Supply	Tuesday, January 01, 2008 1:10:54 AM
What is the requirement on the voltage capacity of the .1uf disc capacitors? I looked at radio shack and the only ones they have listed are 50v. Would this be too much, since the other voltages seem to be 35v?