3 ms·
SMD capacitors are microphonic. They change capacitance slightly when flexed. They also act as speakers, which could be used to exfiltrate data across a (small)
by SAI_Peregrinus 9y ago
SMD capacitors are microphonic. They change capacitance slightly when flexed. They also act as speakers, which could be used to exfiltrate data across a (small) air gap.
- analog31 9y agoI tried making my own guitar amplifier in the early 90s. It had a really mysterious feedback problem. Trying to find the cause, I accidentally brushed across one of the decoupling caps with my scope probe, and it went "doink." It was a big goober of a ceramic disc cap. Lesson learned.
- hazeii 9y agoNot just SMD; pretty much any tuned circuit will ring when tapped (esp. if multi-layer caps are involved, whether SMD or not).