this is a questio on my homework for my automotive electrcal class... Why should a flasher for the turn signals not be interchanged with one for the emergency flashers? I always thought the same flasher was used for both circuits since im only used to seeing one of those round flashers pluged into the fuse box. then again im only really used to working on cars older then me also When should a vehicle be equipped with a heavy-duty turn signal flasher? thanks
my guess, and this a guess only... on the first one, perhaps newer cars are made in a manner that the circuitry is not the same on both applications. perhaps causing an adverse reaction due to the relay not being the correct one. as for the second, id go for instances of towing, or additional lighting. teaching aint like it used to be eh? it used to be all the answers were hidden in the text books, and a bit of reading, and paying attention in class was needed.
I would guess that the blinker relay only has to blink 2 lights ( plus maybe the side markers). The emergency flasher have to blink all the lights so they have to be stouter. I think heavy duty relays are needed if you have a tralor as you are putting more lights into the blinker mix.
ok heres what the book said about heavy duity flashers flashers are designed to operate a specific number of bulbs to give a specific candle power(brightness). If candle power on the turn signal bulbs is changed or if aditional bulbs are used in the circuit like the tail lights and turn signals on a trailer for instance. seems like that would fit in to the answer for both questions.
I've never torn a flasher apart to see how it works but I will take an educated guess. Basic ohms law states, Current = Voltage / resistance. I would guess a flasher uses a bimetal arm where two different metals are bonded together. As current passes through them, they heat up. Because they are different metals, they heat up at different rates, causing the arm to bend. When it bends enough, it breaks contact. When the contacts open, current stops, the arm cools, it bends back, makes contact again, and current once again flows. The amount of current is determined by ohms law. Voltage is constant (12 volts). Resistance is determined by the filament in the bulbs. If they design a flasher to operate turn signals, usually its 3 bulbs, front, rear and dash. For emergency flashers, you are operating twice as many bulbs, or twice the resistance, which by applying ohms law, means half the current. By using half the current, the arm in the flasher may not heat up enough to bend and break contact.
yea thats just about it. that strip heats up as current flows through it and once it gets so hot it curls up and doesnt make contact anymore. it cools and lays back down and makes contact again.
