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2025-10-21 4:21 pm
Hey everyone,
I’m working on a custom drone build and trying to use the 1N4734A zener diode to protect my sensor line from voltage spikes. On paper, it should work fine for my 12 V setup, but in practice, I’m seeing some flickering when the motors spin up.
I’m guessing it’s either placement or how I’ve paired it with the resistor. Has anyone used this zener in a similar setup? Would adding a small capacitor or moving it closer to the load help smooth things out?
Appreciate any advice, just trying to get this circuit stable before I move to final assembly.
2025-10-21 7:26 pm
Hi @jordanm23,
Sorry, but to attempt to answer such a question, I think you need to provide a lot more detail about the 'sensor line' you are trying to protect, as well as something of the nature of the source of interference, and how it is managing to get onto the sensor data wiring.
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Whilst a Zener diode might be able to clip transients, protecting circuits connected to that wire from over voltage damage, they are not often chosen for that purpose. That is not to say a Zener diode could never be used, but rather it is not a 'universal' solution to all such problems.
There are alternate components, typically called 'transient voltage suppressors - TVS' (e.g. see Wikipedia https://en.wikipedia.org/wiki/Transient-voltage-suppression_diode) which behave in a somewhat Zener-like manner, constructed in a robust manner to provide protection against certain hazards, typically hazards which are uncommon in normal operation, but which are sufficiently energetic to risk destroying exposed components.
However, even with such protection (Zener or TVS), the 'data' values returned by the sensor are still liable to be corrupted by noise, which may itself be a problem. Again, it depends upon your situation.
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Sometimes, adding capacitors and/or inductors can be used to block noise, whilst allowing the required data flow, but this also depends upon the characteristics of both the noise sources and the data sources and destinations.
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In general, I would recommend you look to minimise any 'accidental' coupling between the sensor line and sources of noise, such as motors, remembering the coupling may take a variety of forms, including capacitive and inductive coupling between adjacent wires, as well as 'direct' coupling, typically via power (including ground) lines. Stopping the noise getting into the sensitive parts of a system is usually far more effective than trying to remove the noise when it has already corrupted the data. Sadly, in some cases, this can be a challenging task, even for experienced engineers, but in many cases, relatively well-known approaches can be successful. Generally, it means understanding the entire circuit, sometimes including other nearby systems.
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So sorry, this is not a simple answer. Good luck and best wishes, Dave