Transistor basics Flashcards
So that you can properly break down questions and be confident.
How many terminals do transistors have and what are they?
3 terminals: base, collector and emitter.
What are the 3 known types of transistors and which one is mostly used?
Common emitter (90% used), common collector and common base.
How are the 3 known types of transistors classified?
By what terminal is connected to ground.
What type of diode arrangement does the most popular transistor use?
An NPN arrangement.
Why is the most popular transistor used more compared to others?
It is because it’s arrangement makes it the most flexible and it can be easily used to increase voltage or current.
List 3 advantages of transistors?
No moving parts, thus no maintenance.
Bulk manufacture because of tiny size.
Low cost.
Available in multiple packages.
Wide range of I and V ratings.
What term transistor was derived from what two words?
Transfer and resistor.
What difference seperates NPN and PNP type transistors?
The position of the arrow at the emitter. NPN has the arrow facing down, PNP has the resistor facing up (towards the base).
What are the two main functions of a transistor?
To act as an amplifier or to act as a switch.
Within what range in amps does a transistor operate when in the active region?
Between 100uA - 200uA.
When does a transistor act like a closed switch and what is the resulting value of Vce?
Whenever the transistor is saturated and Vce becomes 0V.
When does a transistor act like an open switch and what is the resulting value of Vce?
Whenever the transistor is off and Vce becomes equal to Vin.
What equation should we not use when the transistor is saturated?
Ic = B x Ib
What is the difference between unloaded and loaded base voltage equations?
Unloaded: normal circumstances when Rin is greater than 10(R2) and thus has no effect on Ib.
Loaded: when Rin is less than 10(R2) and thus has an effect on Ib (used for Vb accuracy).
What is an LDR?
A light dependant resistor which changes its electrical resistance from mega ohms in the dark to only a few hundred in bright light.
What is a thermistor?
A temperature dependant resistor which operates with mega ohms in low temp. but low ohms in high temp.
What is the purpose of a freewheel diode?
To dissapate the lingering energy/current that remains in the coil even after being switched off. The transistor will likely be damaged without it.
What amp threshold is needed to switch on an LED?
Above of equal to 10mA.
Can you tell that a transistor has been damaged?
Nope.
What is true about these flash cards?
They are not enough, still visit your notes often.
