Npn transistor Items tagged with Npn transistor

Hi TB,

As our friend pdi33 has put it rightly, you are basically building a freq.counter/meter.

i would suggest to go with 1 sec sampling period, which gives accuracy of 1 Hz.

also what is the max freq./rpm of the engine ?

you can also use a normal NPN transistor like BC547 for connecting the input voltage,
feed the +7V to the base of transitor via a suitable value resistor (4k7/10k) and the collecto... Read Compelte post