4 ms·
Resistance is all you need to know, actually testing the max current is not necessary. Or safe, even.
by rini17 3y ago
Resistance is all you need to know, actually testing the max current is not necessary. Or safe, even.
- iudqnolq 3y agoYou're right, I mixed up USB wall bricks which can have issues like the voltage dropping.
- lsaferite 3y agoNot an EE, but I would hope that testing max current _would_ be safe (at least on a legit cable).
- lxgr 3y agoFor the newer USB-PD modes, you also need to know the maximum safe voltage (and related construction features, such as CC pins being a bit shorter to enable a safe/spark-free connection teardown), or you risk arcing.
- rini17 3y agoAFAIK all cables are de-facto rated up to 30V, as you won't save money if you make insulation even thinner. So this is non issue in practice. Plus you can't really measure breakdown voltage without destroying the cable.
- lxgr 3y agoPD goes up to 48V, though. And I think one important feature is having shorter CC pins in the connector, so that the power source can shut down the high voltage to avoid arcing altogether. That seems to be a feature distinct from insulation.