Contents
Can transistor reduce current?
The transistor (BJT, MOSFET…) doesn’t generate a larger current from a smaller current. It merely allows a low current to control the flow of a much larger current. The large current is provided by a power supply of sort connected to the transistor circuit.
Do transistors affect current?
Transistors can also work as switches. A tiny electric current flowing through one part of a transistor can make a much bigger current flow through another part of it. In other words, the small current switches on the larger one.
How does transistor increase current?
During the negative alternation of the input signal, the transistor current increases because the input voltage aids the forward bias. The output for the negative alternation of the input is a positive alternation of voltage that is larger than the input but has the same sine wave characteristics.
How does a transistor control electric flow?
Transistors do not create electric current, they only control electric current supplied to them. The input current at the base controls the output current flowing between the emitter and the collector. If the base current varies, so does the output current, which is how a transistor functions as an amplifier.
What happens when a transistor is off in a circuit?
When it’s OFF, no current can flow. In the example circuit below, the transistor is OFF. That means no current can flow through it, so the Light-Emitting Diode (LED) is also off. To turn the transistor ON, you need a voltage of about 0.7V between the base and the emitter.
What are the advantages of using a transistor?
The advantage of a transistor is that you can use a small current or voltage to control a much larger current and voltage. That’s super useful if you want to control things like motors, high-power LEDs, speakers, relays, and more from a Raspberry Pi/Arduino/microcontroller.
How are transistors used to control high current loads?
You can use transistors from circuits like these. For example, you might put a transistor on the output pin of a 555 timer IC (which produces a variable timing pulse), or a shift register IC (which allows you to produce multiple control signals in parallel) to control high current loads from those devices.
How is a transistor used in a microcontroller?
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. The output pins of a microcontroller can only produce a small amount of current and voltage. But when coupled with a transistor, they can control much more.