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How can a transistor be used as a switch in a circuit?
One of the most common uses for transistors in an electronic circuit is as simple switches. In short, a transistor conducts current across the collector-emitter path only when a voltage is applied to the base. When no base voltage is present, the switch is off. When base voltage is present, the switch is on.
When a transistor is used as a switch it operates between?
Transistors may be used as switching elements to control DC power to a load. The switched (controlled) current goes between emitter and collector; the controlling current goes between emitter and base. When a transistor has zero current through it, it is said to be in a state of cutoff (fully nonconducting).
How does a transistor work in a circuit?
A transistor works when the electrons and the holes start moving across the two junctions between the n-type and p-type silicon. The small current that we turn on at the base makes a big current flow between the emitter and the collector. So the base current switches the whole transistor on and off.
How is a transistor set up as a switch?
The setup to set the transistor up as a switch is shown in the diagram below: The output of the device that outputs a current will be connected to the base of the transistor. The load will be connected to the collector as well as the positive DC voltage for NPNs. The emitter will connect to ground.
How are two transistors used as an example?
Two transistors as Switch Example In this circuit, there are two transistors. In the first transistor, the base is grounded and no current can flow into it. As a result, the transistor is “off” and no current can flow through the bulb.
What happens when a positive signal is applied to 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 does a transistor control the flow of current?
When we combine a P-type and N-Type semiconductor materials with each other, a junction is formed between them. This junction is also known as a PN junction or a transistor. This PN junction controls the flow of current across the junction. But this junction breaks by applying a proper biasing voltage across transistor pins.