- #1
kvtb
- 11
- 0
Hi,
as mentioned in my previous thread, I'm currently busy with a 'small' project of translating an analog device (synthesizer, based on schematics) into a digital (software) version.
I know 'nothing' about EE, I'm a Computer Science guy, so hopefully this question is not too easy :-)
This question is about how to model the behaviour of a transistor. In the analog device, a single transistor is used as a voltage controlled amplifier.
- The control voltage envelope [tex]V_b(t)[/tex] enters via the base of the transistor,
- the voltage to be shaped according to the envelope [tex]V_c(t)[/tex], enters via the collector
- the output is a voltage [tex]V_e(t)[/tex] of which was until now modeled as simply [tex]V_e(t) = V_b(t) \cdot V_c(t)[/tex]However... later I noticed that every website about transistors say that [tex]I_e = I_b + I_c[/tex], so that would imply that it is impossible to get [tex]V_e(t) = V_b(t) \cdot V_c(t)[/tex]So, my question is simply,
- given a control voltage as function of time [tex]V_b(t)[/tex]
- given an input voltage [tex]V_c(t)[/tex]
How do I calculate [tex]V_e(t)[/tex] in terms of [tex]V_b(t), V_c(t), R1, R2, R3[/tex] and any transistor dependent constants?
Thanks in advance!
as mentioned in my previous thread, I'm currently busy with a 'small' project of translating an analog device (synthesizer, based on schematics) into a digital (software) version.
I know 'nothing' about EE, I'm a Computer Science guy, so hopefully this question is not too easy :-)
This question is about how to model the behaviour of a transistor. In the analog device, a single transistor is used as a voltage controlled amplifier.
- The control voltage envelope [tex]V_b(t)[/tex] enters via the base of the transistor,
- the voltage to be shaped according to the envelope [tex]V_c(t)[/tex], enters via the collector
- the output is a voltage [tex]V_e(t)[/tex] of which was until now modeled as simply [tex]V_e(t) = V_b(t) \cdot V_c(t)[/tex]However... later I noticed that every website about transistors say that [tex]I_e = I_b + I_c[/tex], so that would imply that it is impossible to get [tex]V_e(t) = V_b(t) \cdot V_c(t)[/tex]So, my question is simply,
- given a control voltage as function of time [tex]V_b(t)[/tex]
- given an input voltage [tex]V_c(t)[/tex]
Thanks in advance!