Evo,
Would it be possible to post your new circuit. I have been following the discussions here as I have been having problems driving an LM2917 from a hall effect as well. I'm beginning to think the LM2917 doesn't go too well with hall effect switches.
My idea was to get 0-5 volt output from 0-10,000 rpm input (which I believe is 333 hz approx). By using different combinations of R1C1 using the calculations, I get different "cut-off" points. i.e. the circuit will respond through the entire range if the output voltage is in the millivolt range but if the R1C1 values are changed to give a larger output voltage, the output will only go so far and then stops. With the circuit in attachments, this is about 1.16 Volt at approx. 2,000 rpm (70 hz)
I'm using a circuit I found at :-
http://www.niksula.hut.fi/~mdobruck/siililand/mini/diy/alien/tacho/tacho.html
and changed the input to accomodate the hall effect switch and I see it is very similar to what SgtWookie has suggested.
Would it be possible to post your new circuit. I have been following the discussions here as I have been having problems driving an LM2917 from a hall effect as well. I'm beginning to think the LM2917 doesn't go too well with hall effect switches.
My idea was to get 0-5 volt output from 0-10,000 rpm input (which I believe is 333 hz approx). By using different combinations of R1C1 using the calculations, I get different "cut-off" points. i.e. the circuit will respond through the entire range if the output voltage is in the millivolt range but if the R1C1 values are changed to give a larger output voltage, the output will only go so far and then stops. With the circuit in attachments, this is about 1.16 Volt at approx. 2,000 rpm (70 hz)
I'm using a circuit I found at :-
http://www.niksula.hut.fi/~mdobruck/siililand/mini/diy/alien/tacho/tacho.html
and changed the input to accomodate the hall effect switch and I see it is very similar to what SgtWookie has suggested.
Attachments
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