Chapter 7 Self Test: BJT Biasing - Electronics Principles by Malvino/Bates
Base voltage
For emitter bias, the voltage at the emitter is 0.7 V less than the
Ground
For the emitter bias, the voltage across the emitter resistor is the same as the voltage between the emitter and the
Equal the collector supply voltage
If a splash of solder shorts the collector resistor of TSEB, the collector voltage will
Equal the collector supply voltage
If the base resistor opens with TSEB, the collector voltage will
Increase
If the collector resistance decreases in a VDB circuit, the collector voltage will
Low
If the collector resistor is open, the collector voltage is
Base current
If the current gain is unknown in an emitter-biased circuit, you cannot calculate the
Decreases
If the emitter resistance decreases in a VDB circuit, the collector voltage
Decrease
If the emitter resistance decreases with TSEB, the collector voltage will
Q point moves up
If the emitter resistance decreases, the
Drop in half
If the emitter resistance doubles with TSEB, the collector current will
Increases
If the emitter resistance increases, the collector voltage
Double
If the emitter resistance is reduced by one-half in a VDB circuit, the collector current will
High
If the emitter resistor is open, the collector voltage is
Small
In TSEB, the base current must be very
RB , 0.01 bdc RE
In a TSEB circuit, the base voltage is approximately zero when
Equal to ßdc RE
In a VDB circuit, the base input resistance RIN is
Much smaller than the voltage divider current
In a well-designed VDB circuit, the base current is
Near 0 V
The base voltage of two-supply emitter bias (TSEB) is
Current gain
The collector voltage of a VDB circuit is not sensitive to changes in the
The ratio of collector current to base current
The current gain of a pnp transistor is
Opposite npn currents
The currents of a pnp transistor are
Emitter voltage
The first step in analyzing emitter-based circuits is to find the
Emitter bias
A circuit with a fixed emitter current is called
Switching circuits
Base bias is associated with
Emitter bias
VDB has a stable Q point like
Stable Q point
VDB is noted for its
Only one supply
VDB needs
Active region
VDB normally operates in the
Current gain
The Q point of TSEB does not depend on the
Almost totally insensitive to changes in current gain
The Q point of a VDB circuit is
Increased sensitivity
The major advantage of a phototransistor as compared to a photodiode is its
Holes
The majority carriers in the emitter of a pnp transistor are
Remains almost the same
When the current gain increases from 50 to 300 in an emitter-biased circuit, the collector current
Emitter current
Which is the largest current in a pnp transistor?
Decrease the collector voltage
With VDB, an increase in collector resistance will
0.7 V higher than the base voltage
With a TSEB pnp circuit using a negative VCC supply, the emitter voltage is
Resistors
With pnp voltage-divider bias, you must use
Less than the base supply voltage
With voltage-divider bias, the base voltage is
