What's the function of capacitors in dynamos?

AI Thread Summary
The discussion centers on the function of the 104 capacitor in dynamos, particularly in toy motors. It is identified as a 100nF capacitor, primarily used to suppress electrical noise generated by sparking at the motor's brushes. The placement of the capacitor close to the noise source is noted as good practice. The term "dynamo" is clarified as an outdated reference in the US, historically used for DC machines, while the discussion also touches on the evolution of terminology. The importance of bypass capacitors in motor control applications is acknowledged, highlighting their role in noise reduction.
ChrisToffer
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what is the function of the cap 104, why is it there? what's the function of this cap in the dynamo.. i know caps are used in motors for P.F correction, but what about the dynamos in toys??
 

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probably to 'absorb'(or suppress) the electrical noise from sparking at the motor's brushes.
Observe it's been placed as close to the noise source as physically possible which is good practice.
 
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I agree.
That looks more like a DC motor than a dynamo. The worm gear confirms it.
The 104 capacitor is 10 0000 pF = 100nF and is there to prevent radiation of RF noise from the sparking at the brushes.
 
Dynamo in the US is an outdated term that used to mean generator and/or alternator not sure which. I was wondering if dynamo might just be Aussie for motor in the US?
 
in 1890's it referred to a DC machine which of course can both generate and motor.

As late as 1963 Austin-Healey 3000 labelled its dashboard ammeter with word "Dynamo"
but here the term is quaint.

I once used a small motor like the one pictured and controlled it with a 555 IC. Need for bypass capacitor at motor was immediately obvious.
 

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