This is a placeholder topic for “Voltage Regulator 5V (7805)” comments.
An absolute staple! The ubiquitous L7805 voltage regulator, a three-terminal positive regulator with a 5V fixed output voltage.
Read moreI need a components to step down 24 VDC to 3 Volts DC with a maximum 100mA temperature sensor. How to achieve that?
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Hi Kris
3V or 3V3 ??
Cheers Bob
I just looked and most of the fixed output regulators have a max input of 15V.
I think your best bet would be a LM317TG adjustable device from Core SKU COM-00527. This requires 2 external resistors to set the required voltage (1V2 to 37V). There is a circuit showing its use and resistor calculation in the data sheet linked on Core product page. Max input voltage 40V and will easily handle your 100mA.
You can then set to 3V or 3V3 whichever you need.
Cheers Bob
Hi Robert,
Thanks for answering so quickly it went to spam so I just got it.
My output from the 24 VDC must be dead on 3 VDC since that is replacement for 2 1.5V AAA batteries for the temperature device. My input is going out of AIPHONE module.
Regards Kris
It is quite possible that the device handles a voltage from 3V to 5.5V and the existing system is using the batteries at 3V simply for convenience. You will have much more choice if the device can handle 3.3V (such as, for example, the DS 18B20 temperature sensor). For instance:
Can you post a link to the device you are planning to power using this regulator?
Hi Kris
Fresh AAAs will be a bit over 1.5V anyway so the pair will be probably about 3V3 until discharged a bit.
Cheers Bob
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Thank you
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Hey @Kris300259,
Welcome to the forum!
Glad to see the community was able to steer you in the right direction. Best of luck with your project.
