Скачать или смотреть BZW-04 voltage limiting diode

This little component is what’s known as a TVS diode, and it’s actually intended to be used as a transient voltage suppression device (hence the name) in electronics. However, I found a nonstandard use: as a speed limiter in old Lego 71427 nine volt motors.

I filmed two versions of me cranking it as hard as I can; the first half is with the TVS in place, and the second half is with the TVS removed. In the first half, I struggle to get the motor to spin faster after it generates more than the clipping voltage of the TVS and the motor starts to be loaded; in the second half, without the diode to limit the voltage and absorb the current, I can easily crank the motor so fast that the commutator starts to throw off sparks as the voltage is able to jump between the brushes.

0:00 BZW-04 in place
0:06 BZW-04 removed