problem with a circuit

Thread Starter

mubwandaz

Joined Apr 2, 2015
7
hie guys.i am trying to build a circuit but i am not good at electronics . i am trying to convert pwm of a hall sensor to a voltage out put using a lm2917 tacho chip,then measure the frequency and voltage using an oscilloscope and plot the results on a graph.is it possible to measure these both at the same time.i am using a circuit diagram i found on line but the circuit seems not to be working
thank you
 

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blocco a spirale

Joined Jun 18, 2008
1,546
Without knowing exactly how you have built this, how could anyone even begin to guess as to why it doesn't work. The circuit appears to be from the datasheet, so it should be ok.

Yes, it is possible to measure voltage and frequency at the same time.
 

Thread Starter

mubwandaz

Joined Apr 2, 2015
7
Without knowing exactly how you have built this, how could anyone even begin to guess as to why it doesn't work. The circuit appears to be from the datasheet, so it should be ok.

Yes, it is possible to measure voltage and frequency at the same time.
I am building it on a bread board and using the same circuit diagram I found on line of the lm2917 and added a Hall Effect sensor to the circuit. Similar to the diagrams above
 

blocco a spirale

Joined Jun 18, 2008
1,546
Verify component polarity and values.
Inspect every solder joint.
Check there are no shorts, especially between the copper tracks.
Use a meter to confirm that everything connects exactly where it should and nowhere else.

This is all part of the troubleshooting process that you must learn to do by yourself before seeking assistance. Electronics is an exact science and attention to detail is an essential skill.
 
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Thread Starter

mubwandaz

Joined Apr 2, 2015
7
Also then tried it on a strip board
Verify component polarity and values.
Inspect every solder joint.
Check there are no shorts, especially between the copper tracks.
Use a meter to confirm that everything connects exactly where it should and nowhere else.

This is all part of the troubleshooting process that you must learn to do by yourself before seeking assistance. Electronics is an exact science and attention to detail is an essential skill.
I have checked all tracks. Even used a multi meter to double check connections etc. Maybe I am connecting it wrong to the scope have both probes on output of the chip but have channel one reading voltage and channel two reading frequency
 

Dodgydave

Joined Jun 22, 2012
11,307
your chip is in the wrong way, pins 1,2 have a link in , they should be on pins 5,6.

You have maybe blown the ic up by connecting it backwards.
 
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