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This page was last updated on 7 May 2001

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D C Voltages

 

 

The following tables of dc voltages are provided to assist in initial testing and any fault-finding that may be required. They have been prepared from simulations of the 1969 and 1996 versions. The 1969 version was simulated with a supply rail voltage of 27V and a quiescent current of 1.2A and the 1996 version with +/-22V supply rails and a quiescent current of 2A.

 

The last three columns in the tables have been included to allow calculation of nodal dc voltages at other supply rail voltages. Vs is the supply rail voltage (the value of a single rail for dual-rail supplies), Vbe is the base-emitter potential for a transistor (typically 0.7V) and Iq is the quiescent current.

 

 

1969 Version

 

Device

Emitter

Base

Collector

Emitter

Base

Collector

Tr1

0V

0.7V

13.5V

0

Vbe

Vs / 2

Tr2

13.5V

14.2V

27.0V

Vs / 2

(Vs / 2) + Vbe

Vs

Tr3

0.7V

1.4V

14.3V

Vbe

2.Vbe

(Vs / 2) + Vbe

Tr4

12.9V

12.3V

1.4V

(Vs / 2) – Vbe

(Vs / 2) – 2.Vbe

2.Vbe

 

 

1996 Version

 

Device

Emitter

Base

Collector

Emitter

Base

Collector

Tr1

–22V

–21.3V

0V

–Vs

–Vs + Vbe

0

Tr2

0V

0.7V

21.3V

0

Vbe

Vs – (Iq / 3)

Tr3

–21.3V

–20.5V

0.7V

–Vs + Vbe

–Vs + 2.Vbe

Vbe

Tr4

0.7V

0.1V

–20.5V

Vbe

0.1

–Vs + 2.Vbe

Tr5

21.3V

20.7V

0.7V

Vs – (Iq / 3)

Vs – (Iq / 3) – Vbe

Vbe

 

 

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HISTORY:   Page created 07/05/2001