Following question with topic “Zener Diode lost regulation”

[EDA_hg81]

The new problem is during sampling and holding time of sensor.

The 2.5V Zenzer lost its voltage regulation again.

https://obrazki.elektroda.pl/65_1226680391.jpg
https://obrazki.elektroda.pl/86_1226680442.jpg

I have lowered resistor from 10K to 1.1k and from 1.1k to 500 ohm.
Based on above way the problem is improved a little bit, but I still can’t fix the problem.
What I should do?

Looks like this sensor need to much current ( >8mA).

Should I lower resistor to 250 ohm to generate 10mA current? I am scared.

Which zenzer I should use to replace current one?

Thanks.

 

[eem2am]

sorry from yuor image i cannot see how far the voltage fell or how long it took for the voltage to get back up again.

..remember zeners are always pretty slow devices so will take time to get into regulation.

what about using a TL431 ?...and give it some bias current.

or what about some other type of voltage regulator thats quicker / more responsive

 

[EDA_hg81]

Re: Following question with topic “Zener Diode lost regulati

I fixed it a little bit by connecting two Caps 1UF and 0.1UF

but still not good enough.

how I can make it much better?

https://obrazki.elektroda.pl/84_1226693816.jpg

 

[FvM]

The usual way is to present a circuit and the problem. When starting a follow-up topic without even linking to the original thread (why not simply continuing it?), you can't actually expect serious answers.

If I remember right, you also didn't clearly show your circuit in the original thread, making it difficult to give effective help. As a general remark, I usually have fast OPs as reference buffers, optional with a buffer capacitor and low ohmic isolation resistor (e. g. 0.1 Ohm/10 uF) for pulsed loads to a reference voltage. This may be of course overkill to your application.

 

[Audioguru]

Where is the schematic?