Subscribe to Arduino Academy and start learning today for FREE!

3.3v regulator for our Arduino I2C projects

We are using the onboard 3.3v output on our Arduino board to run the SHT21 temp/humidity sensor. It’s limited to 50 ma, so we are building a 100ma circuit, using the LE33CZ-TR voltage regulator, and two capacitors. We are using a 12v nominal input, but this circuit will handle up to 18v input (for when the house batteries are charging at 14.4 or so, and the occasional 15v equalize).

497-4258-1-ND (LE33CZ-TR 3.3v Regulator) $0.88

BC1148CT-ND (.1 mf 25v ceramic cap) $0.44

445-2866-ND (2.2 mf 25v ceramic cap) $0.26

I will be building a 5v regulator soon as well with the same input requirements, using the LE50CZ-TR 5v regulator, but Digikey did not stock this part at the moment. The inhibit circuit shown does not exist in the 3 leg TO-92 package, only in the surface mount 8 pin SO-8.

Become the Maker you were born to be. Try Arduino Academy for FREE!

Notify of
Inline Feedbacks
View all comments


Would love your thoughts, please comment.x