Hatch & CapacitorX
Hey Hatch, I’ve been looking at the high‑frequency spikes on the power line to the actuator. I want to run a precision RC low‑pass filter with a TVS diode, but I’m worried the resistor value might add noise. How would you tackle that?
Don’t let that resistor scare you – treat it like a stubborn friend and negotiate. Pick a value low enough that the 100 kHz roll‑off is still well below your actuator bandwidth, but not so low it squanders power. Use a 10 kΩ and see what the spectrum says; if the line still buzzes, bump it to 2.2 kΩ and then throw in a small ceramic capacitor, like 0.1 µF, right at the TVS. The TVS will clamp the spikes, the small cap will smooth the edges, and the resistor will only add a negligible hiss if you’re clever about layout – keep the trace short and avoid any loops that could act as an antenna. Test it in the lab, tweak, and if it still trips, give the TVS a new angle; sometimes a 50 V device will sit more quietly than a 30 V one on the same board. The key is keep the resistor as a quiet middleman, not the loudspeaker. Happy tinkering!
Got it. I’ll run a quick sweep with a 10 kΩ followed by 0.1 µF, monitor the line, then switch to 2.2 kΩ if the noise stays. I’ll place the TVS on the high‑voltage side, keep the trace <2 cm, and route it away from any loops. Then I’ll log the results in the log file, note the exact values, and keep the schematic updated. That should give us a clean, stable feed.
Sounds like a solid game plan – just make sure the TVS sits right at the input, not too far away. If the line still whispers, try swapping the capacitor for a 0.22 µF; sometimes a little extra smoothing does wonders. Keep an eye on the temperature on the TVS – those beasts hate heat. Good luck, and remember: if it still glitches, it’s just another mystery for me to solve.
Thanks. I’ll mount the TVS right on the input line, keep the trace short, and log the temperature every minute. If the noise persists, I’ll swap the 0.1 µF for 0.22 µF and update the schematic. Will keep everything in the log file. Let me know if the waveform still hiccups.
All right, you’ve got the plan set – just remember to check that the TVS isn’t turning into a heat‑soup. If the waveform still hiccups, drop a second 0.1 µF right next to the first, or maybe try a ferrite bead on the line. Keep me posted, and we’ll squash that glitch like a stubborn fly on a window. Good luck, champ!
Will log temperature, add the second 0.1 µF, try the ferrite bead, and update the schematic. If the glitch persists, I’ll note the exact values and the waveform again. Will keep you posted.