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[deleted] t1_j8dhx9d wrote

Reply to comment by stt816 in Displaying motorcycle in home..how to power up headlight with plug? by stt816

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mymoparisbestmopar t1_j8dizaa wrote

You're thinking of a rheostat, and those are very outdated for the purpose of dimming lights. Theyre big, inefficient, and get crazy hot. Nowadays most every dimmer youll find, especially in residential electrical, are gonna be solid state dimmers, which use variations on pulse width modulation.

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[deleted] t1_j8dkcjv wrote

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mymoparisbestmopar t1_j8dnixm wrote

*varistor, which is short for varying resistor, a component for which its resistance changes with the applied voltage, meaning it doesnt have a set ohm rating. A potentiometer isnt a varistor, and a varistor wouldnt be a very good dimmer, considering its ability to affect current is dependent on the voltage being applied to it, meaning to use it to dim anything, youd need to be able to dynamically reduce the applied voltage, meaning youd need a dimmer for a varistor to work as a dimmer. Also, the dimmers im talking about are made for AC current, they switch said AC current on/off at an adjustable time after the start of each half cycle, thus modulating the width of the pulses of current sent through the circuit, like i said, a version of pulse width modulation. You ever seen a dimmer switch in a house? Most likely a solid state dimmer.

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[deleted] t1_j8dqqnz wrote

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mymoparisbestmopar t1_j8f1ext wrote

Dude...

Leading edge or trailing edge is the difference of which part of the wave form the dimmer cancels out to reduce the average current in the circuit, thats exactly what i was describing in my comment.

>they switch said AC current on/off at an adjustable time after the start of each half cycle, thus modulating the width of the pulses of current sent through the circuit

Leading edge vs trailing edge is just whether the circuit is turned back OFF during the half cycle, or turned back ON during the half cycle. You literally dont understand the technology enough to recognize a description of how it works. If all the ones youve installed have been leading edge or trailing edge, theyve all been solid state dimmers.

Also, he needs a 120V AC to 12V DC adaptor either way, so honestly he could use an AC dimmer OR a DC dimmer.

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