Hi, this is Wayne again with a topic “DIY Hacks & How To’s: Pocket Sized Power Supply”.
I’M a big fan of garage sales and thrift stores. There are great places to find used parts and materials for your next project, but one problem that i often run into is not being able to test battery-powered electronics to see if they work, because there are so many different combinations of batteries. It isn’t really practical to carry batteries around with you for testing so to solve this problem, i came up with a simple, pocket-sized variable power supply. This lets you power a wide variety of circuits long enough to test them. Here are the parts that you need for this project.
This circuit uses an lm317 variable voltage regulator. This is the same regulator ic that i used in my project on how to replace batteries with an ac power adapter. A typical regulator circuit of this type uses a variable resistor to set the desired output voltage. The only difference with this circuit is that, instead of a variable resistor, i’m using an array of resistors and switches to adjust the output voltage in discrete increments. This makes it a lot easier to simulate individual batteries. The circuit can be powered by either a 9-volt battery or a 12-volt battery pack after prototyping the circuit on a breadboard. I soldered everything together on a small perf board, now you’re ready to try out your new miniature power supply, here’s how it works. Turning on switch 1 turns the circuit on and brings the output up to 1.25 volts, then turning off switches 2-8 in sequence, will each increase the output by 1.5 volts up to a limit that’s set by the supply voltage.
Now, whenever you want to test something, just set the switches to give the appropriate output voltage and connect the alligator clips to the battery connectors on the device, this system is a lot more convenient to carry around with you just wrap the wires and the battery connector Around the circuit board and it will easily fit in your pocket. Well, thanks for watching and check back next week for more diy hacks and how to’s .