Hi guys. I have researched this topic A LOT. In fact, I found these forums as a result. Evidently, it has been asked here before (Google knows all!). Mine has a slight twist to it. All the research I have done so far has been about people wanting to run a continuous 9v load off a 12v source. Mine will be for a fraction of a second at a time. Project: I want to hardwire a 9v garage door remote into my motorcycle's low-beam circuit. The jumpers under the activation button on the remote will be soldered together so as to keep it permanently primed to send the pulse if power is provided. I would then solder wires into the remote's battery terminals and splice the positive wire into the power wire of the low-beam circuit while -ve will naturally be grounded. I always ride the bike with my high beam on so the idea is to get close to the garage, switch from high to low for a fraction of a second and switch back. That should open/close the door. Questions: - Do I even need to drop the voltage if I will be powering the remote for such short bursts? If for any reason, I am forced to have the low-beam on for an extended period (i.e. the high-beam coil burns out while on an unlit road at night), would it immediately fry the remote's circuitry? - I was thinking of using a single 1K Ohm resistor and wiring it in series with the low-beam wire and the remote. I came across http://www.bcae1.com/resistrs.htm which suggests that per Ohm's Law a resistor in a circuit takes all the load, BUT they don't say what would happen in my proposed scenario if the voltage is measure forwards of a single resistor. I am sure it would drop somewhat. - My research has pointed me to zener diodes as well. But I am thoroughly perplexed by how they work. Are they the answer?