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9V DC Power Supply

mrob

New Member
While searching for a 9V DC power supply for my project, I see that many recommend external components. For example, see this pair on Amazon. Here's the recommended circuit:
1745678922231.png

I understand that the components are for ripple, interference, and circuit protection. But before I start integrating this into my design, I was hoping to find a "ready made" supply, without breaking the bank. Any recommendations? If not, I will have several follow-up questions about the external components.

The project is for 20 white LEDs on bunk bed stairs with a PIR motion sensor. The LEDs will be wired as 10 parallel circuits with two LEDs in series for each circuit. A resister will be added to each of the 10 circuits to dimly light the LEDs. I expect the current draw to be under 500mA.

Thanks in advance. It's been about 35 years since I've played with this stuff.
 
While searching for a 9V DC power supply for my project, I see that many recommend external components. For example, see this pair on Amazon. Here's the recommended circuit:
View attachment 149675
I understand that the components are for ripple, interference, and circuit protection. But before I start integrating this into my design, I was hoping to find a "ready made" supply, without breaking the bank. Any recommendations? If not, I will have several follow-up questions about the external components.

The project is for 20 white LEDs on bunk bed stairs with a PIR motion sensor. The LEDs will be wired as 10 parallel circuits with two LEDs in series for each circuit. A resister will be added to each of the 10 circuits to dimly light the LEDs. I expect the current draw to be under 500mA.

Thanks in advance. It's been about 35 years since I've played with this stuff.
If you're wiring this to a bunk bed, I assume there are sleeping children near by. As you ask, I would focus on pre-made supplies with short circuit protection and even splash protection. You never know what happens in a kids bedroom with pee, tea, fights (you said bunk beds).

Also, I'd recommend 12v and use some very common strip light LEDs. On most, you can just cut on the 1" mark and you get 3 LEDs per inch with a current limiting resistor. Many are sold with a dimming circuit and a remote control brightness unit. All for under $20 in many cases for 3meters of LEDs.
 
You might take a look at your local thrift stores. They often have an abundance of "wall wart" power supplies for a buck or two. 9 volt supplies will be less common, but 12 volt supplies should be easy to find. Adjust the series resistor values as needed.
 

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