Voltage Divider Question

[aberco]

I don't really know what I did but I get accurate readings now... who knows! I'll try to understand it later on and post it here.

[malc-c]

Anyone know how to reduce voltage but still provide suitable current.

A friend needs to reduce 24v DC to 12v DC, but needs to drive a load of around 250mA. Whilst voltage dividers work well at providing a reference voltage, they appear impractical when you place a load across (ie in parallel with) the second resistor.

Using a 12v regulator is also impractical for him as the heat generated to dissipate 12V means it requires a large heatsink.

[aberco]

What about a switching regulator? they are usually quite efficient and don't require an heatsink. 250mA is not much, and I'm sure that even an LDO (low dropout regulator) could perform well. 7812 has a large voltage drop and tends to heat.

You can look at the catalog from TI, Maxim, ST and others, they most certainly have the device that suits your need (i.e. TL750M12 from TI in TO220 package)

[Ioannis]

Or from RECOM. Just like a 78xx regulator, only switching. No heat sinking required.

Ioannis

[malc-c]

Thanks guys - I'll pass on the suggestions. Can you provide a part number or link for the RECOM switching regulator - Cheers

[Ioannis]

Sure, here it is for 1A. There are others for .5 or 1.5A

http://www.recom-international.com/?...user_recom_pi2[series]=R-78Bxx-1.0(L)

Ioannis

[malc-c]

Thanks - I'll pass on the info