![]() ![]() The first curve shows how the BE diode responds to the current set by the Vcc - Rb circuit. (I drew them by hand after running a simulation with a 2n2222A and a 2.1 LED to get coherent values). You ask for a simple curve to illustrate how the circuit is behaving. How do I figure out how much resistance it will take to turn the transistor off?Īnd does anyone know of a simple curve that can help illustrate how the transistor is behaving in relation to the changing resistance on the emitter? I looked at the technical specs for this device that shows some plots but I honestly couldn't make heads or tails of them. I was also surprised to learn that the transistor consistently dropped around 3V no matter how much current was coming into the emitter. I was even more surprised that and additional 10 1M resistors were not enough to shut it down, though the LED was very dim. I was very surprised to see that 10 100K resistors were not enough to turn the transistor off. With a jumper, I can crudely vary the current flowing into the emitter. ![]() Simulate this circuit – Schematic created using CircuitLab Not having a large potentiometer, I set up the following circuit, using all the large value resistors that came with the kit: Included in the kit was a couple of PN2222 transistor. I bought my kid an Arduino kit to give him a basic taste for how electronic circuits work. It's been about 30 years since I studied transistors so please forgive my basic question.
0 Comments
Leave a Reply. |