24 volt regulator

You could look into "low dropout regulators" which are linear regulators designed to operate with a minimum voltage between the input and output of the regulator(across the series pass transistor). I'm not sure what the minimum may be...possibly as low as 0.1V which might be ok for you're application. Check out

----------------------------------------------- Steve M -

Hello. I want to build a simple DC voltage regulator circuit. I don't care about ripple because the voltage is from batteries. THe normal voltage is 24 but sometimes the voltage goes high at 28. The idea is too make a circuit that lets the voltage pass when i have 24 volts and to regulate them to 24 when i have 28.

Any help?

You don't say how much current you need.

You could use the combination of a linear regulator and a relay. Switch in the relay when the voltage gets down below the dropout.

There are buck regulators that could be used to get you down within a volt or so.

You could also use a shunt regulator, but that would drain your battery pretty quickly. A zener diode across the power rails is a form of shunt regulator.