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## Re: Electrical Theory

 To: Fred Pixley Re: Electrical Theory Rick Huber Tue, 04 May 1999 17:45:35 -0500
 Fred and others, Since I started this brake switch is hot thread, I thought I'd throw my 2 cents in. In my tiny mind I understand it this way. Voltage is like the pressure of water in a pipe and current is like the flow of water through the pipe. Resistance to flow causes pressure drop, roughly equivalent to power. With the system energized with the 12 volt battery to an open switch, there is pressure, or 12 volts available to the switch, but no current flow, like pressure up to a spray nozzle on the hose. Once the switch is closed, when you press the brake pedal, 12 volts is available to the light bulb. If the ground past the bulb is open, i.e. not grounded, then there is 12 volts available through the whole circuit, but still no current flow. Once the ground past the bulb is closed, as much current flows through the system as the element in the bulb will allow (it's the orifice or the spray nozzle on the hose), so the element is like an orifice in a pipe. 12 volts upstream, current flow of a couple of amps through the element, producing power and therefore light and heat, and then much lower voltage on the downstream side of the bulb back to ground. As has been said already, normally, there is essentially no resistance anywhere in the circuit except at the light bulb element. However, when the contacts in the switch become corroded over 24 years, they become the resistance in the circuit more than the elements in the bulb, so the power is taken across the contacts in the switch and it gets hot. Downstream of this orifice, there's not enough voltage left to light the bulbs. The analogy here is a kink in the hose upstream of the nozzle, therefore no flow through the nozzle when it's open. So what I did was take the switch apart, clean the contacts very thoroughly (remove the kink in the hose), and now I have brake lights again. It seems so simple now trying to explain it, why couldn't I figure it our this easily when I was troubleshooting? Safety Fast, Rick Huber 75 V8 B Daily Driver 65 B undergoing lengthy restoration
 Current Thread Electrical Theory, Fred Pixley Re: Electrical Theory, Robert Alan Reisse Re: Electrical Theory, Robert Alan Reisse Re: Electrical Theory, dresden Re: Electrical Theory, Rick Huber <= Re: Electrical Theory, REwald9535 Re: Electrical Theory, Ajhsys Re: Electrical Theory, REwald9535 Re: Electrical Theory, JSMcC Re: Electrical Theory, Paul Hunt