Slope change detector circuit

[jszair]

I want to build a slope change/increase detector to detect increase of voltage slope, and generate a notification signal when the increase happens.

Any ideas of reference I should look at?

Thanks!

 

[barry]

You could use a simple differentiator circuit (output proportional to slope).

 

[BradtheRad]

Assuming the signal is slowly changing DC...

You can install a capacitor in series, the same way as you would use it for DC blocking.

The capacitor will not pass slow changes in applied voltage (if you choose the value properly).

A more rapid change will come through the capacitor.

This describes a basic concept using analog components. Similar to a differentiator (as mentioned in post #2).

You can amplify the changes in volt level. Feed it to comparators/opamps.

Adjust the output to remain in a middle range when slope changes slowly or not at all.

However a fast enough change will cause the output to swing more strongly.

You can set a hi threshold in one comparator. Set a low threshold in another comparator. To trigger your alert device.

 

[goldsmith]

Dear jszair
Hi
As i understood , you want design a simple slope change ,detector . i think below circuit can help you . its out put will be a dc voltage at the max amplitude of your sine input.




Best Wishes
Goldsmith

 

[poorchava]

If voltage changes slowly, then I'd just attenuate/amplify (anyway, condition the signal) and then sample with ADC built into microcontroller.

If you specifically need to design an analog circuit, then it depends what are the frequencies. At some fractions of Hz capacitor leakage current plays significant role.

 

[barry]

goldsmith, what you've got there is a peak detector; it's not going to tell anything about slope.

 

[goldsmith]

Dear Barry
Hi
Yes you're right , i sent that circuit by misunderstanding .
Thanks
Goldsmith