Electric OU: How DO Mosfets Work? Another LITTLE Step Forward?

If you already know what I show in this video, and know that it is not faked, you are obviously NOT an illiterate ignoramus. OTOH, if the shoe fits, you can wear it proudly.

Here I use 3 ea. AA batteries as the negative bias source, and show the Common Gate Amplifier turning on with a DC signal from the AA batteries, lighting up the #161 14V bulb brilliantly. Then I remove the bulb and replace it with the more linear power resistor and I add a battery to the Main stack to make it 24 V. Then I show the OSCILLATIONS happening with the DC input signal from the AA batteries. Then I remove the AA battery bias supply and hook up the FG just where it was…. and lo and behold the OSCILLATIONS.

NOTE the disclaimer at the end of the video: For this demo to work properly you must not create a groundloop, since the Scope Probe reference is not at the same place as the Black FG lead. This can be done in two ways (at least.) You can float the FG by isolating its Black lead from the system ground by cutting the Green line cord wire, or by using the FG’s isolation switch if it has one (mine does) and assuring that no other instruments are connected to the FG, OR you can simply disconnect the Scope Probe reference from the Source pin of the mosfet. The former method is preferred since it gives a cleaner and more accurate trace on the scope; in this video I used the latter method since the Scope Probe Reference clip came disconnected on its own when I jiggled the mosfet just prior to hooking up the FG.

NOTE THIS WELL: sometimes with the low battery voltage this system will not oscillate when the bias AA stack connection is made, as you can see in this video a couple of times. When that happens, the mosfet is turned FULLY ON, and so conducts the full current supplied by the battery through the load as DC. This will of course heat up both the load, rapidly, and the mosfet, a bit more slowly. SO do not let yourselves be fooled by even this simple circuit: proper ground reference connections must be used, no groundloop allowed, and the circuit must be monitored to assure that you are oscillating and not just turning the mosfet on hard.

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