frequency to voltage circuit with LM2907

eetech00

Joined Jun 8, 2013
1,790
The LM2907 is typically used for frequencies in the low kHz range at most. I can't find any upper limit in the datasheet, but I can't see it working for anything much higher. Incidentally, that IC is now obsolete.
The chip isn’t obsolete. Or, at least I couldn’t find that stated on TI’s site.

I don’t think the chip usable past 10khz.
I think even 8khz is pushing it...
eT
 

eetech00

Joined Jun 8, 2013
1,790
now it work good, and I can see Vout changes as the Vin and/or the Vcc modified.
Thank you.


Now I need to do some reverse engineering, I need to modify this circuit so it will measure the output of torque sensor,
the output of the sensor is phase displacement.

how can I simulate phase displacement in LTSpice?
Did you actually breadboard the circuit to verify it works?

eT
 

MisterBill2

Joined Jan 23, 2018
4,929
It probably will be around 8Ghz but I don't know the phase shift itself.
thats what I want to simulate
Suddenly changing the whole game to measuring phase shift from a torque sensor is quite a switch. At this point a more complete description of the project, including the intended results, is in order. That is to say that it no longer makes any sense at all, at least from what I see.
 

Thread Starter

Tamir

Joined Jul 11, 2018
10
today I tested the circuit, my input was 10v and 0-10Khz
with Vcc=15v the output was 0-14v.


I did some changes in the circuit so at 10Khz it will be 14V, hopefully when I connect it to the engine it will give me the result that I want, but time will tell.


Suddenly changing the whole game to measuring phase shift from a torque sensor is quite a switch. At this point a more complete description of the project, including the intended results, is in order. That is to say that it no longer makes any sense at all, at least from what I see.
I'm building one circuit for 2 purposes, one to read from tachometer sensor, and another one to read from torque sensor.
in both sensors the output is frequency but it's 2 different applications.


Thank you all for your help
it's really appreciated.
 

MisterBill2

Joined Jan 23, 2018
4,929
There has been a great deal of effort spent in selling the concept of engine torque sensors, the makers of torque sensors are really working to start a fad But gas engine torque can be calculated based on engine manifold vacuum and throttle position. Chrysler did that for many years with their smart carburetor system. Much cheaper MUCH more reliable, and the math can even be done in an alalog system.
 
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