Inductor Boost Voltage Video

Demonstrates some basic power uses of an inductor in a ‘chopped’ DC circuit. Chopping the current through the inductor demonstrates Lenz’s Law states If an induced current flows, its direction is always such that it will oppose the change which produced it, so opening an inductive circuit will result in a back emf, which here is used to add to the source voltage.  This inductor has an inductance measured at 950mH and it’s feeding into a 1k ohm load with a 47uF cap across the load resistor.  The chopper transistor is an NPN BD139…. not a particularly high Vce max, so the demo is conducted at just 5 volts.  Without the capacitor, the output voltage spikes to 35V .. so if a higher input voltage was used, the Vce max rating of this transistor would easily be breached.  The large value of inductance allows us to use very low frequencies for this demonstration. GM May’16