How to use a transistor as a switch Circuit Diagram These pins are meant to send control signals, not to act as power supplies. The most common way to control another direct current device from a microcontroller is to use a transistor. Transistors allow you to control the flow of a high-current circuit from a low-current source. Video: Transistor Schematics Video: Meet the motors
Here's how to set up both the BJT and the MOSFET transistor as a switch so you can easily control things like motors, lamps, and more.
How to Use Transistor as a Switch with Example Circuits Circuit Diagram
Figure 7 shows the basic circuit for using a transistor to control a high-current load. You connect a DC power source to one terminal of the load, then connect the second terminal of the load to the collector of the transistor (or drain, for a MOSFET) of the transistor.
If we want to connect a load that requires a higher operating current demand of more than 3mA, it will burn the microcontroller. Many output devices will require a transistor switching circuit to operate a high current requirement load, such as relays, solenoids, and motors. How to use it?
Lab: Using a Transistor to Control a High Current Load Circuit Diagram
Introduction Transistors are often used as electronic switches, to control loads which require high voltage and current from a lower voltage and current. The most common example you'll see of this in a physical computing class is to use an output pin of a microcontroller to turn on a motor or other high current device. For the transistor to operate as a switch, a principle of the small base current controlling the large collector load current is used. If you want to control large currents, use the Darlington transistor as a switch If this type of switching arrangement is acceptable, then the low-side switch is usually the cheapest way to achieve load switching. BJT Low-Side Switch A BJT can be used as a load switch and come in two flavors: NPN and PNP. For low-side switching, NPN transistors are used, and for high-side switching a PNP is used.
