What is the difference in applying -ve voltage at emitter and +ve coll

[dexterdev]

What is the difference in applying -ve voltage at emitter and +ve voltage at collector in attached circuit image? Really what I think is both circuits in thae image are identical. But then why -VEE?

-Devanand T

 

[vk6kro]

The power supply voltages also affect the necessary input voltages.

For example in the second diagram, the transistor with -1.3 volts on its base will be turned off if the negative supply line is grounded but it is conducting if this line is at -5.2 volts.

This is because the base is more positive than the negative supply line in the second case, but less positive in the first case.

 

[NascentOxygen]

What is the difference in applying -ve voltage at emitter and +ve voltage at collector in attached circuit image? Really what I think is both circuits in thae image are identical. But then why -VEE?

-Devanand T

Over what range of input voltages will the arrangement in (a) function as an amplifier?

What about (b)?

 

[dexterdev]

the circuit in (a) is basic ECL unit, range of inputs is 2 logic states at input -1.7 V and -0.8 V.

I was asking that what difference (a) has with (b) in voltage supply applied in terms of polarity.

 

[NascentOxygen]

the circuit in (a) is basic ECL unit, range of inputs is 2 logic states at input -1.7 V and -0.8 V.

I was asking that what difference (a) has with (b) in voltage supply applied in terms of polarity.

(b) will function in the same manner, but not with the input/output voltages that cause (a) to work.