Lesson 10 The PNP Transistor

Chapter Lesson 10 The PNP Transistor

Electronic Circuits for the Evil Genius Second Edition 64 Lessons with Projects
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Electronic Circuits for the Evil Genius Second Edition 64 Lessons with Projects

  • 34Section 3 ■More Components and Semiconductors8.Press and release the push button. After yourelease the push button, what part provides thepower to the base of the transistor?__________________________________________________________________________9.Describe the path of the current that providesthe power to the LED. Here is something toconsider regarding the answer. The capacitoris not powering the LED. It is only poweringthe transistor.10.Record three time trials of how long the LEDstays on with the 10-microfarad capacitor.Replace C1 with the 100-microfaradcapacitor. Time the LED here for three timesas well, and find the average.Roughly stated, how much more time didthe 100-microfarad capacitor keep the LED onfor than the 10-microfarad capacitor?a.Three times longerb.Five times longerc.Eight times longerd. Ten times longerWrite down your prediction of how muchtime the 1,000-microfarad capacitor wouldkeep the LED working.Okay, now put in your 1,000-microfaradcapacitor. Try it out three times, and averagethe time.How accurate was your prediction?11.Describe in detail how this circuit works.Consulting Figure L8-22 of the capacitorpowering the LED once the push button isreleased, the voltage pressure to the base isprovided by the________________________.Lesson 10The PNP TransistorWe use only the NPN 3904 and PNP 3906. Theserepresent the two general classifications oftransistors. They are evenly matched but oppositein their action.The identity of the legs on the TO92 packagestays the same, as shown in Figure L10-1. But lookclosely at the symbol for the PNP in Figure L10-02.Note that the schematic symbol of the transistorholds some important information. The arrowinside the schematic symbol still points in thedirection of the common current, but is on the topside now. Because it is always on the side of theemitter, that means the PNP emitters and collectorsTime 1Time 2Time 3Average____ s____ s____ s____ sTime 1Time 2Time 3Average____ s____ s____ s____ sTime 1Time 2Time 3Average____ s____ s____ s____ sFigure L10-1Figure L10-2