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Step 3Fixed Voltage Regulators
Check the documentation that came with the chip you use to verify the pin-outs. Similar chips typically share pin-outs, but never assume.
On my chip, pin one is the input, pin 2 is the output, and pin 3 is the ground. Note that pin 3 is between pins 1 and 2. The left to right sequence is 1,3,2 (not 1,2,3). I have seen 1,2,3 configurations with 2 as ground and 3 as output by some manufacturers. It's really only the numbers that change, the ground is still in the center, and output is still the rightmost pin, but get in the habit of knowing your chip before applying power.
Run your bare wall wart wires to the binding posts on a solderless breadboard, and then wires from the posts to the breadboard tie-points inline with the input and ground on the chip. Next run jumper wires from the output pin to the power rail, and from the ground pin to the ground rail (see the photo). That's it! You now have a regulated voltage.
Add your 78XX chip to an otherwise finished circuit. I once cracked open a wall wart and installed one right inside. It worked great and continues to work to this day despite having been powering a small video camera 24/7 since 2003. Of course, I drilled holes in the wall wart case for ventilation. Still, I don't really recommend this "in-wart" approach. Wall warts are a pain to open, and these chips can get quite hot in the right circumstances.
On my chip, pin one is the input, pin 2 is the output, and pin 3 is the ground. Note that pin 3 is between pins 1 and 2. The left to right sequence is 1,3,2 (not 1,2,3). I have seen 1,2,3 configurations with 2 as ground and 3 as output by some manufacturers. It's really only the numbers that change, the ground is still in the center, and output is still the rightmost pin, but get in the habit of knowing your chip before applying power.
Run your bare wall wart wires to the binding posts on a solderless breadboard, and then wires from the posts to the breadboard tie-points inline with the input and ground on the chip. Next run jumper wires from the output pin to the power rail, and from the ground pin to the ground rail (see the photo). That's it! You now have a regulated voltage.
Add your 78XX chip to an otherwise finished circuit. I once cracked open a wall wart and installed one right inside. It worked great and continues to work to this day despite having been powering a small video camera 24/7 since 2003. Of course, I drilled holes in the wall wart case for ventilation. Still, I don't really recommend this "in-wart" approach. Wall warts are a pain to open, and these chips can get quite hot in the right circumstances.
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