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Introduction: In some books and other technical papers (also from universities) it is - surprisingly - still claimed that the bipolar transistor (BJT) would be a current-controlled element. This is...
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transistor
#4: Post edited
by
Lorenzo Donati
·
2023-08-02T08:27:00Z (9 months ago)
Removed premise that is irrelevant to the question, but it is something about the rules of the website.
As I have learned, it is allowed to ask a question here to which I already know one of several possible answers.- **Introduction**: In some books and other technical papers (also from universities) it is - surprisingly - still claimed that the bipolar transistor (BJT) would be a current-controlled element. This is simply stated - without any explanation or proof (which I think is impossible).
- But of course, the other representation (voltage-controlled) can also be found in many knowledge sources - just as it is considered in the SPICE models.
- For me and also for many students this is an unsatisfactory situation. Therefore, I consider the distinction (current vs. voltage-control) to be very important to avoid contradictions between theory and practice.
- Because many circuits and observable effects can only be explained with voltage control Ic=f(Vbe).
- As one argument pro current control often the output characteristic Ic=f(Vce) is referred to, where the base current Ib is considered as a fixed parameter (Ib=const).
- And - as a matter of fact: Although the collector current Ic is determined by the voltage Vbe, the characteristic curves Ic=f(Vce) are practically always given only for different (fixed) base currents Ib.
- **My Question**: Why ?
- **EDIT**: In response to Elliot Alderson`s comment I enclose a short contribution from the great Barrie Gilbert.
- 
- **Introduction**: In some books and other technical papers (also from universities) it is - surprisingly - still claimed that the bipolar transistor (BJT) would be a current-controlled element. This is simply stated - without any explanation or proof (which I think is impossible).
- But of course, the other representation (voltage-controlled) can also be found in many knowledge sources - just as it is considered in the SPICE models.
- For me and also for many students this is an unsatisfactory situation. Therefore, I consider the distinction (current vs. voltage-control) to be very important to avoid contradictions between theory and practice.
- Because many circuits and observable effects can only be explained with voltage control Ic=f(Vbe).
- As one argument pro current control often the output characteristic Ic=f(Vce) is referred to, where the base current Ib is considered as a fixed parameter (Ib=const).
- And - as a matter of fact: Although the collector current Ic is determined by the voltage Vbe, the characteristic curves Ic=f(Vce) are practically always given only for different (fixed) base currents Ib.
- **My Question**: Why ?
- **EDIT**: In response to Elliot Alderson`s comment I enclose a short contribution from the great Barrie Gilbert.
- 
#3: Post edited
by
LvW
·
2020-10-22T18:51:17Z (over 3 years ago)
- As I have learned, it is allowed to ask a question here to which I already know one of several possible answers.
- **Introduction**: In some books and other technical papers (also from universities) it is - surprisingly - still claimed that the bipolar transistor (BJT) would be a current-controlled element. This is simply stated - without any explanation or proof (which I think is impossible).
- But of course, the other representation (voltage-controlled) can also be found in many knowledge sources - just as it is considered in the SPICE models.
- For me and also for many students this is an unsatisfactory situation. Therefore, I consider the distinction (current vs. voltage-control) to be very important to avoid contradictions between theory and practice.
- Because many circuits and observable effects can only be explained with voltage control Ic=f(Vbe).
- As one argument pro current control often the output characteristic Ic=f(Vce) is referred to, where the base current Ib is considered as a fixed parameter (Ib=const).
- And - as a matter of fact: Although the collector current Ic is determined by the voltage Vbe, the characteristic curves Ic=f(Vce) are practically always given only for different (fixed) base currents Ib.
- **My Question**: Why ?
- **EDIT**: In response to Elliot Alderson`s comment I enclose a short contribution from the great Barrie Gilbert.
- 
- As I have learned, it is allowed to ask a question here to which I already know one of several possible answers.
- **Introduction**: In some books and other technical papers (also from universities) it is - surprisingly - still claimed that the bipolar transistor (BJT) would be a current-controlled element. This is simply stated - without any explanation or proof (which I think is impossible).
- But of course, the other representation (voltage-controlled) can also be found in many knowledge sources - just as it is considered in the SPICE models.
- For me and also for many students this is an unsatisfactory situation. Therefore, I consider the distinction (current vs. voltage-control) to be very important to avoid contradictions between theory and practice.
- Because many circuits and observable effects can only be explained with voltage control Ic=f(Vbe).
- As one argument pro current control often the output characteristic Ic=f(Vce) is referred to, where the base current Ib is considered as a fixed parameter (Ib=const).
- And - as a matter of fact: Although the collector current Ic is determined by the voltage Vbe, the characteristic curves Ic=f(Vce) are practically always given only for different (fixed) base currents Ib.
- **My Question**: Why ?
- **EDIT**: In response to Elliot Alderson`s comment I enclose a short contribution from the great Barrie Gilbert.
- 
#2: Post edited
by
LvW
·
2020-10-22T18:49:34Z (over 3 years ago)
- As I have learned, it is allowed to ask a question here to which I already know one of several possible answers.
- **Introduction**: In some books and other technical papers (also from universities) it is - surprisingly - still claimed that the bipolar transistor (BJT) would be a current-controlled element. This is simply stated - without any explanation or proof (which I think is impossible).
- But of course, the other representation (voltage-controlled) can also be found in many knowledge sources - just as it is considered in the SPICE models.
- For me and also for many students this is an unsatisfactory situation. Therefore, I consider the distinction (current vs. voltage-control) to be very important to avoid contradictions between theory and practice.
- Because many circuits and observable effects can only be explained with voltage control Ic=f(Vbe).
- As one argument pro current control often the output characteristic Ic=f(Vce) is referred to, where the base current Ib is considered as a fixed parameter (Ib=const).
- And - as a matter of fact: Although the collector current Ic is determined by the voltage Vbe, the characteristic curves Ic=f(Vce) are practically always given only for different (fixed) base currents Ib.
- **My Question**: Why ?
- As I have learned, it is allowed to ask a question here to which I already know one of several possible answers.
- **Introduction**: In some books and other technical papers (also from universities) it is - surprisingly - still claimed that the bipolar transistor (BJT) would be a current-controlled element. This is simply stated - without any explanation or proof (which I think is impossible).
- But of course, the other representation (voltage-controlled) can also be found in many knowledge sources - just as it is considered in the SPICE models.
- For me and also for many students this is an unsatisfactory situation. Therefore, I consider the distinction (current vs. voltage-control) to be very important to avoid contradictions between theory and practice.
- Because many circuits and observable effects can only be explained with voltage control Ic=f(Vbe).
- As one argument pro current control often the output characteristic Ic=f(Vce) is referred to, where the base current Ib is considered as a fixed parameter (Ib=const).
- And - as a matter of fact: Although the collector current Ic is determined by the voltage Vbe, the characteristic curves Ic=f(Vce) are practically always given only for different (fixed) base currents Ib.
- **My Question**: Why ?
- **EDIT**: In response to Elliot Alderson`s comment I enclose a short contribution from the great Barrie Gilbert.
- 
#1: Initial revision
by
LvW
·
2020-10-19T15:48:37Z (over 3 years ago)
Why Ib=const. for BJT output characteristics Ic=f(Vce)
As I have learned, it is allowed to ask a question here to which I already know one of several possible answers. **Introduction**: In some books and other technical papers (also from universities) it is - surprisingly - still claimed that the bipolar transistor (BJT) would be a current-controlled element. This is simply stated - without any explanation or proof (which I think is impossible). But of course, the other representation (voltage-controlled) can also be found in many knowledge sources - just as it is considered in the SPICE models. For me and also for many students this is an unsatisfactory situation. Therefore, I consider the distinction (current vs. voltage-control) to be very important to avoid contradictions between theory and practice. Because many circuits and observable effects can only be explained with voltage control Ic=f(Vbe). As one argument pro current control often the output characteristic Ic=f(Vce) is referred to, where the base current Ib is considered as a fixed parameter (Ib=const). And - as a matter of fact: Although the collector current Ic is determined by the voltage Vbe, the characteristic curves Ic=f(Vce) are practically always given only for different (fixed) base currents Ib. **My Question**: Why ?