Hi all,
I am using a 7805 voltage regulator to power a chip, but an input signal going to one of its pins is coming as a +14V. How do I bring down this +input to an adequate voltage level to the chip?
I am thinking to use a voltage divider.
Any other ideas?
Thanks

 

yep use two resistors, no diode required, use a R1=10k and R2=4k7

 

Any other ideas?

The divider is a fine way to go. Probably no reason to consider anything else.

Some other thoughts: Are you sure the chip cannot tolerate the 14v input? Maybe it's not a problem.
You could use a zener on the chip's input. Depending on the impedance of the source of the signal, you may or may not need a current limiting resistor to protect that zener from over-current.
There are plenty of other ways to condition a signal, too. You can use a comparator or a schmitt trigger to square it up and send forward whatever voltage you want. Optoisolator is another choice.

 

Thanks Dodgydave. Will play around with those resistors values as the voltage can also
go down to ~12.5v. (r1=15k, R2=10K)

 

Great ideas Wayneh. I will try the Zener and Opto options too. I am not sure how
I would bias the schmitt trigger.

 

Many chips have clamping diodes. You only need to limit the current, for instance 10 or 12 KOhms.

 

Hope we are talking digital here.

If the signal is analog, with a zener it would be not clamped but totally clipped.