Physics and Python stuff. Most of the videos here are either adapted from class lectures or solving physics problems. I really like to use numerical calculations without all the fancy programming ...

A quartz crystal's case will be stamped with the devices' rated operating frequency, but that number is only an approximation to the real story which is that there is more than one crystal resonant ...

A parallel circuit is way of connecting components on separate branches, so the current can take different routes around the circuit. The current is different in different parts of a parallel circuit.