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Project Notes

#152 LD1117 Regulator

Test an LD1117 3.3V linear regulator

The Build

Notes

The LD1117 is a low drop fixed and adjustable voltage regulator, available from a number of manufacturers including UTC and ST. Parts are available for a range of output voltages, including: 1.2V, 1.5V, 1.8V, 2.5V, 2.85V, 3.0V, 3.3V, 3.6V, 5.0V, and ADJ.

The component I have is marked: UTC LD1117AL 33D010HT5

Although I can’t find a datasheet that matches these markings exactly, I figure:

  • A = 1A
  • L = lead free
  • 33 = 3.3V
  • D? = pin out is (from left front): Vin, Ground, Vout

Note that the LD1117A by ST has a different pin configuration for the TO220 package. From pin 1 left front: Ground, Vout, Vin.

Some DMM measurements, with a 10kΩ output load:

Vin Iin Vout Iout Pin:Pout
5.10V 2.47mA 3.30V 329µA 12.6mW : 1.09mW

The inefficiency of a linear regulator is clear to see - we’re dissipating 11.51mW in the 1117, far more power than is actually delivered to the load. But they’re convenient!

Construction

Breadboard

The Schematic

The Build

Credits and References

About LEAP#152 Power
Project Source on GitHub Return to the LEAP Catalog

LEAP is just my personal collection of electronics projects - usually involving an Arduino or other microprocessor in one way or another. Some are full-blown projects, while many are trivial breadboard experiments, intended to learn and explore something interesting.

Projects are often inspired by things found wild on the net, or ideas from the many great electronics podcasts and YouTube channels. Feel free to borrow liberally, and if you spot any issues do let me know (or send a PR!). See the individual projects for credits where due.

For a while I have also included various scale modelling projects here too, but I've now split those off into a new repository. Check out LittleModelArt if you are looking for the modelling projects!

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