I am trying to make a voltage clamp. It is for automotive and 3 wires run to a sensor 5v, gnd, and signal 0-5v. I am looking to clamp the voltage between 4.2v-4.5v as in it will have to be adjustable because different settings depending on weather and such. I know I can use a zener diote and potentiometer I believe but not sure on wiring it up. I saw this thread: http://forum.allaboutcircuits.com/showthread.php?t=2647 But still confused on wiring it as there is no pictures and no very good description. From what I understand one wire on the potentiometer gets spliced into 5v and the other end to GND and the middle signal wire would get wired to the zener diode and then SPLICED into the signal wire. I don't get how splicing would clamp the voltage because I made a test circuit but no matter what the LED gets 5v. I am using a 4.5v zener diode.