Amazon.com: 50 pcs of 2N4401 NPN & 50 pcs of 2N4403 PNP Transistor / General Purpose Amplifier : Industrial & Scientific
Multifunction Meter DIY kit, ACEIRMC Mega 328 Graphic Transistor Tester, NPN PNP Diodes Triode Capacitor ESR SCR MOSFET Resistor Inductance LCD Display Checker with case: Amazon.com: Industrial & Scientific
AUTONICS BEN10M-TDT NPN & PNP Output, Light & Dark ON, 12-24 VDC, Through Beam, Photo, Sensor: Electronic Component Photoelectric Sensors: Amazon.com: Industrial & Scientific
Amazon.com: PNP NPN Transistors Kit, Three Pins Silicon Power Transistor Assorted Assortment Box Set Range 2N3904-MPS2907, 10Value,Pack of 200, by Ltvystore : Industrial & Scientific