Reported by: Aaron Fredriel De Guzman

COLLECTOR-EMITTER LOOP

By Kirchoff’s Voltage Law:

+

Since,

Therefore,

Collector-Emitter Loop

Voltage from E to Gnd:

Voltage from C to Gnd:

Or

Collector-Emitter Loop

GIVEN:

β= 20Find:

Collector-Emitter Loop

To find :We use:

Collector-Emitter Loop

Using

mA

Collector-Emitter Loop

For

(470Ω)2.04V

Collector-Emitter Loop

For

(470Ω)2.04V

For

4.34mA)(330Ω)

Collector-Emitter Loop

We can find

Collector-Emitter Loop

Reported by: Aaron Fredriel De Guzman

IMPROVED BIAS STABILITY

The addition of the emitter resistor to the DC bias of the BJT provides improved stability, that is, the dc bias currents and voltages remain closer to where they were set by the circuit when outside conditions, such as temperature and transistor beta, change.

IMPROVED BIAS STABILITY

From the example given:

IMPROVED BIAS STABILITY

At β=20

Increasing the beta (β) from the given to 40 and

80

IMPROVED BIAS STABILITY

β (μA) (mA) (V)20 217 4.34 9.39

40 177.92 7.117 9

80 130.86 10.47 8.53