Transistors Electrical circuit diagram Power 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?
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
Lab: Using a Transistor to Control High Current Loads with an Arduino ... Circuit Diagram
However, if you are delivering power to an entire circuit or a voltage-sensitive device, then you want to use a high-side switch. By the way, there are off-the-shelf components called " load switches." These ICs have a P-Channel MOSFET as the switching transistor with a built-in driver for that P-Channel.
When we need to switch moderate to high levels of power, one of the best methods we can use is a transistor with an open-collector output. In this setup, we connect the emitter terminal of the transistor directly to ground.
Using Transistor Switching Circuit Diagram
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. 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.
Electronics Tutorial about the Transistor as a Switch and using the Transistor as a Switch to operate relays, motors, lamps and other such loads
