What is the function of NPN transistor BJT to the circuit?
As well as being used as a semiconductor switch to turn load currents “ON” or “OFF” by controlling the Base signal to the transistor in either its saturation or cut-off regions, Bipolar NPN Transistors can also be used in its active region to produce a circuit which will amplify any small AC signal applied to its Base …
What is BJT and its application?
Bipolar transistors (bipolar junction transistors: BJTs) can control the collector current via the current applied to the base. It is this gain that allows bipolar transistors to be used as amplifiers. Bipolar transistors are also utilized as switches using their characteristics in the saturation and cut-off regions.
How is a BJT used as an example?
Using a BJT as a Switch: An Example. Remember that the controlled current through a transistor must go between collector and emitter. Since it is the current through the lamp that we want to control, we must position the collector and emitter of our transistor where the two contacts of the switch were.
How to analyze BJT circuit with d.c.sources?
To analyze BJT circuit with D.C. sources, we mustfollow these five steps: 1. ASSUME an operating mode 2. ENFORCE the equality conditions of that mode. 3. ANALYZE the circuit with the enforced conditions. 4. CHECK the inequality conditions of the mode for consistency with original assumption.
Why is the base of a BJT not connected to the base?
In the above figures, the base of either BJT is not connected to a suitable voltage, and no current is flowing through the base. Consequently, the transistor cannot turn on. Perhaps, the simplest thing to do would be to connect a switch between the base and collector wires of the transistor as in figure (a) below.
What are the qualitative characteristic curves of a BJT?
Figure 7 shows the qualitative characteristic curves of a BJT. The plot indicates the four regions of operation: the saturation, the cutoff, the active and the breakdown. Each family of curves is drawn for a different base current and in this plot I> I> I>I 4B3B2B1