What is it called when 2 light switches control 1 light?
Electricians call this a 3-way switch because there are three devices in the circuit: two switches and one light. Now that you know the definition of 3-way, I’ll bet you can guess what 2-way and and 4-way switch controls consists of:An [math]n[/math]-way switch control will use two 3-way switches and [math]n-3[/math] four-way switches.Only three types of switches are needed to make any multiway switching circuit:Single pole single throw (SPST) two terminal,Single pole double throw (SPDT) three terminal,Double pole double throw (DPDT) four terminal.So why is it called a three way when there are only two switches? Here is my hypothesis.Perhaps when multiway switching was first strating to be used, the light fixture had a separate switch like a common desk lamp or like, in other countries (not the U.S), where outlets have a control switch that switches the outlet on and off. For that configuration, there would be three ways the light could be controlled. Hence, they called it a three way. Then as light fixtures started being wired without the extra fixture switch, electricians still called it a three way because the wiring was the same even though it was technically a two way.
How to change names on a handgun registration...?
I recently turned 21 and want to change my fathers name from my handgun registration. What is the easiest way to put my name on the registration now that I am of age?
Name three characteristics of magnetic reversal?
Not a real clear question but magnetic reversal is where what we know as magnetic north switches to what we now call the south pole. It was discovered because of sea floor spreading when the molten iron particles would align themselves to the magnetic field as the rock cooled - along the ridge where the sea floor is spreading, there are symmetrical stripes where there are periods where the iron particles are aligned this way, and other periods where they are aligned that way. Knowing how fast the sea floor is spreading, they can tell how long the magnetic north was our north and how long it was in a reverse period. P.S. I don't earth scientists really know why this happens or what becomes of the Earths magnetic field as it is switching (becomes erratic because, as you may know, the magnetic north can move around - then weakens - then switches, I'd guess) We may be moving into a period where the poles are erratic an weakening - perhaps the Earth is due for a reversal.
Light switch wiring - red wire on a single pole switch?
I'm replacing a single pole light switch that controls my rear porch light. I removed the old switch and it had the normal black and white wires going into the quickwire holes but additionally a red wire secured with the upper screw on the side. My understand is that you're meant to use either the screws or the quickwire on a single pole switch, so this seems a little hokey. The red wire is coming from the circuit of another switch in the box for the dining room light. Does attaching the red wire to this single pole switch end the circuit? I don't understand why it's necessary or what to do with it. There is only one switch for the porch light, so it should be single pole - I've installed a three-way switch for now so that the red is where it belongs. It works fine this way, but I want to understand and make sure I've found a good solution. Thanks.