When everything is hooked together, the NPN/PNP pair causes the LED to light up, but the circuit is broken whenever one of the transistors is removed.

There are numerous differences between NPN and PNP transistors, and even though both are bipolar junction transistors, the direction of current flow is the name of the game.

Two days later I had a “SainSmart Mega328 Transistor Tester Diode Triode Capacitance ESR Meter MOS/PNP/NPN L/C/R” in my hands. I’m going to get the obvious out of the way.

TI developed its high-speed process to include complementary NPN and PNP transistors, which also benefit from the high speeds of SiGe. The 0.4-mm emitter NPNs and PNPs are rated with a gain ...