Though there are many uses for these running linearly, these are typically used as "electronic switches" in a "saturated mode". Take for instance you want to to drive a device that needs more current than an Arduino can provide. You can use these as external switches to supply the current needed to drive the device (motor's, large LED's, etc.).
Streamline Your Prototyping Work With WayinTop Jumper Wire Kit - Preformed & Flexible Breadboard Jumper Wires With Tweezer Tool
7 Review
Friencity Digital To Analog Audio Converter, Optical To RCA Converter, SPDIF(Toslink) Coaxial To Stereo L/R AUX Adapter W/Optical Cable For TV Amps Blu-Ray Player PS4 Home Cinema, Plug N Play
6 Review
4PCS Breadboards Kit Include 2PCS 830 Point 2PCS 400 Point Solderless Breadboards For Proto Shield Distribution Connecting Blocks
14 Review
Douk Audio U2 PRO XMOS XU208 Digital Interface - USB To TOSLINK/Coaxial/Optical/HDMI IIS Adapter For DAC, Preamp & Amplifier | PCM & DSD256 Support
21 Review