How does a micro transistor work?
A transistor works when the electrons and the holes start moving across the two junctions between the n-type and p-type silicon. By turning a small input current into a large output current, the transistor acts like an amplifier. But it also acts like a switch at the same time.
How do you turn on a transistor?
With a zero signal applied to the Base of the transistor it turns “OFF” acting like an open switch and zero collector current flows. With a positive signal applied to the Base of the transistor it turns “ON” acting like a closed switch and maximum circuit current flows through the device.
How is a transistor used to control a microcontroller?
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.
Can a microcontroller be used as a switch?
A semiconductor device acts as a switch. In this diagram, we can provide a control signal with any microcontroller such as Arduino, STM32F4 development boards. A resistor with a base terminal is a current limiting resistor. Because GPIO pins of any microcontroller can provide base driving current less than 20mA.
Can a microcontroller control a high current load?
In this tutorial, you’ll learn how to control a high-current DC load such as a DC motor or an incandescent light from a microcontroller. Microcontrollers can only output a very small amount of current from their output pins. These pins are meant to send control signals, not to act as power supplies.
How much current does a microcontroller need to drive a led?
Assuming the hFE minimum is 100; the minimum current required in the transistor’s base terminal to drive the LED is: This current can easily be supplied by most microcontroller I/O port; which is capable to drive up to 20 mA output current. Again by applying the Ohm’s law we could calculate the RB value as follow: