Question about circuit

Hi all , this is a tachometer circuit in this page..

Please see it ..

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as the author wrote "Therefore if the output is linear then we have 1V

for every 2000rpm. "

i want to make it 2v or more for every 2000 RPM .

How can i do this ??

Thanks a lot :)

Reply to
ahonda55
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Here is the data sheet for the chip:

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Read page 7.

There are a couple ways to increase the output by a factor of 2. You could double the size of the timing capacitor, C1, or you could double the value of the load resistor, R1. Or you could change both values such that their product is twice the listed values for C1 and R1.

Reply to
John Popelish

Thank you very much I did that already , but i need to increase the (sensetivity) of the tachometer for example, at 2000 RPM 1v , at 4000 RPM it should be 2v , i want to make it 3v or more.

i will try to reduce the (ref. high) in the LED driver IC LM3914, i think it may work .

if it worked i wil post the result here.

Thanx a lot

Reply to
ahonda55

From the datasheet John mentioned: Vout = Vcc * Fin * R1 * C1 * K (K generally equals 1) Try changing C1 from 47 nF to 100 nF and see if that gives you what you want.

Ed

Reply to
ehsjr

i will do that and see if it works.

i dunno how to thank you Ed :) and all of you :)

Reply to
ahonda55

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