A circuit remains passive until a single active component is added, so an RC or LC network is still passive. A piezo buzzer has an equivalent circuit of entirely passive elements, so it is also a ...

Figure an Arduino ... the buzzer to a DC supply with the DMM in series, set to a current range. Trying to directly measure the R of the buzzer will be inconclusive - it's an active circuit ...

Since [Chuck] only had a short bit of time and a tiny budget to work on, he opted to find the easiest solution to the problem, which was an Arduino-based game show buzzer system. The game display ...