keyswitch horn (science)

[fairdeal]

I learned something yesterday;

the horn on the Yamaha keyswitch is polarity dependent:

if the (+) and (-) contacts are reversed it will not sound.

Don't have a guess as to why that should be - guess I'll have to Google it...

[boscoe99]

Most electronic devices are polarity sensitive.

http://www.eng.utah.edu/~cs5789/handouts/piezo.pdf

[99yam40]

I learned something yesterday;

the horn on the Yamaha keyswitch is polarity dependent:

if the (+) and (-) contacts are reversed it will not sound.

Don't have a guess as to why that should be - guess I'll have to Google it...

A diode in the circuit would be my guess

[fairdeal]

as Boscoe explains, its a piezoelectric device:

"A signal is applied to the crystal, which responds by flexing in proportion to the voltage applied across the crystal's surfaces, thus converting electrical energy into mechanical."

Either i wasn't paying attention that day, or my education pre-dated their use.

I was thinking magnet and coil....

but now there's the mystery of why it works on "straight DC" - seems there needs to be oscillating current...

[fairdeal]

Either i wasn't paying attention that day, or my education pre-dated their use.

LOL ! Wikipedia:

''Piezoelectric buzzers, or piezo buzzers, as they are sometimes called,
were invented by Japanese manufacturers and fitted into a wide array of products during the 1970s to 1980s.
This advancement mainly came about because of cooperative efforts by Japanese manufacturing companies."

[fairdeal]

A diode in the circuit would be my guess

on the integral "circuit board" which creates the oscillating feed

[

[pstephens46]

Those Yamaha key switches last a long time, and will last a lot longer if you keep them out of direct sunlight.
I leave the keys in mine (F225s (2005) because the spot where the key sits "dry rots" and a new key switch is than called for at over $400 (two key switch).

Never had a failure in thousands of starts with the Yamaha KS assembly - unlike the Evinrudes key switches (on 11 brand new 225s) which had faulty horns and alarms (and no starts) to drive you nuts.

You can buy new silicone covers for the key switches for about $2.00.

[boscoe99]

Some useless trivia.

[99yam40]

seems I remember someone putting a Radioshack buzzer in a Outboard alarm system(do not remember what brand), that caused some problems.

Just saying it is best to use the correct parts when replacing things

[boscoe99]

seems I remember someone putting a Radioshack buzzer in a Outboard alarm system(do not remember what brand), that caused some problems.

Just saying it is best to use the correct parts when replacing things

Yep, nothing like putting a 5 amp current draw component into a system designed for a milliamp draw component, thus burning out a thousand dollar component trying to save two dollars.

See penny wise and pound foolish.

[rodbolt17]

the new one is a piezio device.
the old one is simply a coil of wire, a disc and a contactor.


a piezio cystal is a wonder.
no the japs did not invent it.
I think it was Motorola.

that crystal has a unique function.
if you shock it it shakes.
if you shake it ,it shocks.

it is used on a lot of gas grills.

that is why you get that big thwak when you push the ignite button.

it shakes the crystal and the crystal generates a voltage.

if you apply a voltage to it it will viberate at a specific frequency, that is why you can also find them in frequency generators.

[pstephens46]

They must be delicate. They last about 6-12 months on a gas grill.

[boscoe99]

They must be delicate. They last about 6-12 months on a gas grill.

But ain't they magic while they work? Press a button and get a spark.

I am so old I remember when matches were a newfangled idea.

[ausnoelm]

They actually last a very long time, usually something else causes them to not spark, the device is simple and reliable.

[Reel Kahuna]

I am so old I remember when matches were a newfangled idea.

Hell that's not old, back in the day I used two rocks to spark a fire .