All things graphs

How do you calculate dynamic resistance from and IV graph

Calculate the gradient by using a tangent - ohms law

Where is the operating point

A specified point on the graph

What are the IV characteristics for an ideal diode in forward bias

No voltage drop and current flowing

What are the IV characteristics for an ideal diode in reverse bias

No current flowing but a voltage drop

What are the V characteristics for a practical diode in forward bias

Voltage increases untill biasing voltage and then stops increasing.

What are the V characteristics for a practical diode in reverse bias

The increasing voltage is all dropped over the diode

What are the I characteristics in an practical diode in forward bias

No current flow until biasing voltage is reached and then maximum current flow

What is the I characteristics of an practical diode in reverse bias

No current flow

What happens to a tunnel diode in forward bias between A and B

The diode will start conducting after a very small amount of voltage and the current increases

What happens to a tunnel diode in forward bias between B and C

It shows negative resistance, and a potential barrier will start to form again

What happens to a tunnel diode in forward bias after point C

It begins to act as a normal diode again

What would the time period of the wave give

The time period of the waveform at the output of the diode

Where is best to operated a Zener diode (graphical)

The knee

What does this graph show

The relationship between Vce and Ic for different Ib

What is the condition for the cut of region

Ib = 0

Why must I_B = 0 to be in cut of region

As the base will not be conducting as it is either in reverse bias or not forward bias enough to conduct

If ideally there is no base current in cut off region, what is the actual approximation

A small amount of leakage current

What is the condition to be in active region (Transistor)

Vce is high enough that is more positive than base and emitter

What is the condition for saturation region

Vce is low so both junctions are forward bias

Why does I_B not significantly increase I_c in the saturation region

As the collector is saturated so its ability to take more current is limited by its voltage not Ib

What does the almost flat lines in the active region show for the relationship between I_C and V_CE

Vce does not effect Ic in this region

Why is the saturation region shaped like that

As both junctions are forward bias, charges flood the base quickly

What does V_CEsat stand for (BJTs)

The collector - emitter saturation voltage

What is V_CEsat (BJT)

The max value at which the transistor is still in the saturation region

What do you need to sketch a collector curve (BJTs)

Ic, Ib and Vce

What is a load line (BJT)

A straight line used to explain the behavior of the BJT in the 3 modes

What does a load line represent (BJTs)

The voltage and current in the linear portion of the circuit

What are the points called where the load line intercepts with the curves

Q points

What is a Q point

The optimal operation in the active region for that value of Ib

What two points do you need to draw a load line

Vce=Vcc and Ic = Icsat

What are FETs controlled by

Voltage

What does FET stand for

Field effect transistors

Which is more temperature stable, FETs or BJTs

FETs

What is on the x-axis of a drain characteristic graph (JFET)

Vds

What is on the Y axis of a drain characteristic graph (JFET)

Id

At what point on a drain characteristic graph (JFET) does I_D flatten off

Idss

On a drain characteristic graph (JFET) what is the value of V_GS for I_DSS

0

What happens to the line on the drain characteristic graph (JFET) when V_GS is less than zero (-1, -2)

It looks the same but the current levels off at a lower value

What is this graph called

Transfer characteristic curve

What is plotted on a transfer characteristic curve (JFETs)

Id Vs Vgs

What is on the X axis of a transfer characteristic curve (JFETs)

Vgs

What is the max I_D value for a transfer characteristic curve (JFETs)

Idss

What is on the Y axis of a transfer characteristic curve (JFETs)

Id

What is the min value for V_GS for a transfer characteristic curve

Vp

What are the IV characteristics for a MOSFET with V_gs = 0 the same as

JFET

Why does I_D level off for the MOSFET

As a depletion region is caused by an electric field attracting the electrons out of the channel leaving very few charge carriers

What is the output of a comparator is the non inverting terminal is higher than the inverting

High signal

What is the output of a comparator where the input at the non inverting terminal is less than the inverting terminal

Low signal

What does the comparators output vary between

Two constant outputs with different polarities

Why does the voltage decrease after going over V_BR

When the device goes into saturation mode, voltage drops to very small but in active region there would be a voltage drop across the collector emitter junction

What is this graph

The IV characteristics of a thyristor

What will happen to V_BR when a pulse is applied

It will decrease

What does the impact of I_G tell us about V_BR

A lower external potential will be required if there is a positive impulse on the gain terminal

What happens to V_BR as I_G increases

It decreases

How can current be decreased below I_H

Decreasing the applied potential or having a circuit in place to do it

What values does I_g not effect

Switchover and holding values

If a SCR does not work for both directions of voltage, what does work

DIAC and TRIAC

What is a DIAC

A 4 layer device that can conduct with both polarities of applied potential

What is this the IV graph for

Shockley diode

What is this IV graph for

SCR

What is this IV graph for

DIAC

When is V_BR at its max in a TRIAC

When Ig = 0

What is this graph for

TRAIC