- #1
anita1984
- 34
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Little Problem with phototransistor !
Hi Forum ,i am using a laser module, phototransistor SFH309-5, and 74HC14N (Circuit in the attachment) to detect the speed of the motor. On the Vout2 i measured frequency up to 2,8KHz when the speed of the motor is 28 000 RPM (because 6 reflected beam every rotation). But when i increase the motor to 32 000 RPM the frequency on Vout2 is 500Hz , and it should be 3,2KHz , what can be the problem ?
Thank you in advance ,
Hi Forum ,i am using a laser module, phototransistor SFH309-5, and 74HC14N (Circuit in the attachment) to detect the speed of the motor. On the Vout2 i measured frequency up to 2,8KHz when the speed of the motor is 28 000 RPM (because 6 reflected beam every rotation). But when i increase the motor to 32 000 RPM the frequency on Vout2 is 500Hz , and it should be 3,2KHz , what can be the problem ?
Thank you in advance ,