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I fully agree with OP considerations about measuring the transistor output curve. We can very easily and precisely set successive current values with constant increment. Thus, the IV curves will be...
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#6: Post edited
by
Circuit fantasist
·
2020-10-21T10:58:26Z (about 4 years ago)
Added related link
- I fully agree with OP considerations about measuring the transistor output curve. We can very easily and precisely set successive current values with constant increment. Thus, the IV curves will be evenly spaced vertically (equidistant from each other).
- Let me generalize these observations into a "golden rule":
- **Golden rule 1:** If you want to set precisely the voltage across and current through a voltage-stable non-linear element (diode, base-emitter junction of a transistor), drive it by a current source. Otherwise (if you control it with a voltage source), the current will change rapidly and it will be difficult to set the operating point. It is interesting that, in other applications (such as a differential pair), this effect (aka "current steering") is useful.
- We can formulate another but dual "golden rule":
- **Golden rule 2:** If you want to set precisely the voltage across and current through a current-stable non-linear element (collector-emitter junction of a transistor), drive it by a voltage source. Otherwise (if you control it with a current source), the voltage will change rapidly and it will be difficult to set the operating point. As above, there are applications (e.g., the so-called "dynamic load") where this effect is useful.
- Finally, we can combine them into a more general "golden rule":
- **Golden rule 3:** If you want to set precisely the voltage across and current through a non-linear element, drive it by the opposite kind of source.
- > Are there further arguments for publishing the output characteristics for Ib=const and not for Vbe=const.
Maybe the Earley effect? Or the temperature dependence?
- I fully agree with OP considerations about measuring the transistor output curve. We can very easily and precisely set successive current values with constant increment. Thus, the IV curves will be evenly spaced vertically (equidistant from each other).
- Let me generalize these observations into a "golden rule":
- **Golden rule 1:** If you want to set precisely the voltage across and current through a voltage-stable non-linear element (diode, base-emitter junction of a transistor), drive it by a current source. Otherwise (if you control it with a voltage source), the current will change rapidly and it will be difficult to set the operating point. It is interesting that, in other applications (such as a differential pair), this effect (aka "current steering") is useful.
- We can formulate another but dual "golden rule":
- **Golden rule 2:** If you want to set precisely the voltage across and current through a current-stable non-linear element (collector-emitter junction of a transistor), drive it by a voltage source. Otherwise (if you control it with a current source), the voltage will change rapidly and it will be difficult to set the operating point. As above, there are applications (e.g., the so-called "dynamic load") where this effect is useful.
- Finally, we can combine them into a more general "golden rule":
- **Golden rule 3:** If you want to set precisely the voltage across and current through a non-linear element, drive it by the opposite kind of source.
- > Are there further arguments for publishing the output characteristics for Ib=const and not for Vbe=const.
- Maybe the Earley effect? Or the temperature dependence?
- ----------------------
- I remembered that I asked such a question in RG network a few years ago - [Why do we use Ib instead Vbe as a parameter when measuring common-emitter output characteristics?](https://www.researchgate.net/post/Why_do_we_use_Ib_instead_Vbe_as_a_parameter_when_measuring_common-emitter_output_characteristics)
- Maybe the discussion there can help...
#5: Post edited
by
Circuit fantasist
·
2020-10-20T06:36:04Z (about 4 years ago)
Added another reason
- I fully agree with OP considerations about measuring the transistor output curve. We can very easily and precisely set successive current values with constant increment. Thus, the IV curves will be evenly spaced vertically (equidistant from each other).
- Let me generalize these observations into a "golden rule":
- **Golden rule 1:** If you want to set precisely the voltage across and current through a voltage-stable non-linear element (diode, base-emitter junction of a transistor), drive it by a current source. Otherwise (if you control it with a voltage source), the current will change rapidly and it will be difficult to set the operating point. It is interesting that, in other applications (such as a differential pair), this effect (aka "current steering") is useful.
- We can formulate another but dual "golden rule":
- **Golden rule 2:** If you want to set precisely the voltage across and current through a current-stable non-linear element (collector-emitter junction of a transistor), drive it by a voltage source. Otherwise (if you control it with a current source), the voltage will change rapidly and it will be difficult to set the operating point. As above, there are applications (e.g., the so-called "dynamic load") where this effect is useful.
- Finally, we can combine them into a more general "golden rule":
- **Golden rule 3:** If you want to set precisely the voltage across and current through a non-linear element, drive it by the opposite kind of source.
- > Are there further arguments for publishing the output characteristics for Ib=const and not for Vbe=const.
Maybe the Earley effect?
- I fully agree with OP considerations about measuring the transistor output curve. We can very easily and precisely set successive current values with constant increment. Thus, the IV curves will be evenly spaced vertically (equidistant from each other).
- Let me generalize these observations into a "golden rule":
- **Golden rule 1:** If you want to set precisely the voltage across and current through a voltage-stable non-linear element (diode, base-emitter junction of a transistor), drive it by a current source. Otherwise (if you control it with a voltage source), the current will change rapidly and it will be difficult to set the operating point. It is interesting that, in other applications (such as a differential pair), this effect (aka "current steering") is useful.
- We can formulate another but dual "golden rule":
- **Golden rule 2:** If you want to set precisely the voltage across and current through a current-stable non-linear element (collector-emitter junction of a transistor), drive it by a voltage source. Otherwise (if you control it with a current source), the voltage will change rapidly and it will be difficult to set the operating point. As above, there are applications (e.g., the so-called "dynamic load") where this effect is useful.
- Finally, we can combine them into a more general "golden rule":
- **Golden rule 3:** If you want to set precisely the voltage across and current through a non-linear element, drive it by the opposite kind of source.
- > Are there further arguments for publishing the output characteristics for Ib=const and not for Vbe=const.
- Maybe the Earley effect? Or the temperature dependence?
#4: Post edited
by
Circuit fantasist
·
2020-10-19T20:55:13Z (about 4 years ago)
Minor edit
- I fully agree with OP considerations about measuring the transistor output curve. We can very easily and precisely set successive current values with constant increment. Thus, the IV curves will be evenly spaced vertically (equidistant from each other).
Let me generalize these observations into a "golden rule 1":1. If you want to set precisely the voltage across and current through a voltage-stable non-linear element (diode, base-emitter junction of a transistor), drive it by a current source. Otherwise (if you control it with a voltage source), the current will change rapidly and it will be difficult to set the operating point. It is interesting that, in other applications (such as a differential pair), this effect (aka "current steering") is useful.We can formulate also a dual "golden rule 2":2. If you want to set precisely the voltage across and current through a current-stable non-linear element (collector-emitter junction of a transistor), drive it by a voltage source. Otherwise (if you control it with a current source), the voltage will change rapidly and it will be difficult to set the operating point. As above, there are applications (e.g., the so-called "dynamic load") where this effect is useful.Finally, we can combine them into a more general "golden rule 3":3. If you want to set precisely the voltage across and current through a non-linear element, drive it by the opposite kind of source.- > Are there further arguments for publishing the output characteristics for Ib=const and not for Vbe=const.
- Maybe the Earley effect?
- I fully agree with OP considerations about measuring the transistor output curve. We can very easily and precisely set successive current values with constant increment. Thus, the IV curves will be evenly spaced vertically (equidistant from each other).
- Let me generalize these observations into a "golden rule":
- **Golden rule 1:** If you want to set precisely the voltage across and current through a voltage-stable non-linear element (diode, base-emitter junction of a transistor), drive it by a current source. Otherwise (if you control it with a voltage source), the current will change rapidly and it will be difficult to set the operating point. It is interesting that, in other applications (such as a differential pair), this effect (aka "current steering") is useful.
- We can formulate another but dual "golden rule":
- **Golden rule 2:** If you want to set precisely the voltage across and current through a current-stable non-linear element (collector-emitter junction of a transistor), drive it by a voltage source. Otherwise (if you control it with a current source), the voltage will change rapidly and it will be difficult to set the operating point. As above, there are applications (e.g., the so-called "dynamic load") where this effect is useful.
- Finally, we can combine them into a more general "golden rule":
- **Golden rule 3:** If you want to set precisely the voltage across and current through a non-linear element, drive it by the opposite kind of source.
- > Are there further arguments for publishing the output characteristics for Ib=const and not for Vbe=const.
- Maybe the Earley effect?
#3: Post edited
by
Circuit fantasist
·
2020-10-19T20:51:24Z (about 4 years ago)
Numbering the rules
- I fully agree with OP considerations about measuring the transistor output curve. We can very easily and precisely set successive current values with constant increment. Thus, the IV curves will be evenly spaced vertically (equidistant from each other).
Let me generalize these observations into a "golden rule":- 1. If you want to set precisely the voltage across and current through a voltage-stable non-linear element (diode, base-emitter junction of a transistor), drive it by a current source. Otherwise (if you control it with a voltage source), the current will change rapidly and it will be difficult to set the operating point. It is interesting that, in other applications (such as a differential pair), this effect (aka "current steering") is useful.
We can formulate also a dual "golden rule":- 2. If you want to set precisely the voltage across and current through a current-stable non-linear element (collector-emitter junction of a transistor), drive it by a voltage source. Otherwise (if you control it with a current source), the voltage will change rapidly and it will be difficult to set the operating point. As above, there are applications (e.g., the so-called "dynamic load") where this effect is useful.
Finally, we can combine them into a more general "golden rule":- 3. If you want to set precisely the voltage across and current through a non-linear element, drive it by the opposite kind of source.
- > Are there further arguments for publishing the output characteristics for Ib=const and not for Vbe=const.
- Maybe the Earley effect?
- I fully agree with OP considerations about measuring the transistor output curve. We can very easily and precisely set successive current values with constant increment. Thus, the IV curves will be evenly spaced vertically (equidistant from each other).
- Let me generalize these observations into a "golden rule 1":
- 1. If you want to set precisely the voltage across and current through a voltage-stable non-linear element (diode, base-emitter junction of a transistor), drive it by a current source. Otherwise (if you control it with a voltage source), the current will change rapidly and it will be difficult to set the operating point. It is interesting that, in other applications (such as a differential pair), this effect (aka "current steering") is useful.
- We can formulate also a dual "golden rule 2":
- 2. If you want to set precisely the voltage across and current through a current-stable non-linear element (collector-emitter junction of a transistor), drive it by a voltage source. Otherwise (if you control it with a current source), the voltage will change rapidly and it will be difficult to set the operating point. As above, there are applications (e.g., the so-called "dynamic load") where this effect is useful.
- Finally, we can combine them into a more general "golden rule 3":
- 3. If you want to set precisely the voltage across and current through a non-linear element, drive it by the opposite kind of source.
- > Are there further arguments for publishing the output characteristics for Ib=const and not for Vbe=const.
- Maybe the Earley effect?
#2: Post edited
by
Circuit fantasist
·
2020-10-19T20:20:21Z (about 4 years ago)
Minor edit
I fully agree with OP considerations. We can very easily and precisely set successive current values with constant increment. Thus, the IV curves will be evenly spaced vertically (equidistant from each other).- Let me generalize these observations into a "golden rule":
- 1. If you want to set precisely the voltage across and current through a voltage-stable non-linear element (diode, base-emitter junction of a transistor), drive it by a current source. Otherwise (if you control it with a voltage source), the current will change rapidly and it will be difficult to set the operating point. It is interesting that, in other applications (such as a differential pair), this effect (aka "current steering") is useful.
- We can formulate also a dual "golden rule":
- 2. If you want to set precisely the voltage across and current through a current-stable non-linear element (collector-emitter junction of a transistor), drive it by a voltage source. Otherwise (if you control it with a current source), the voltage will change rapidly and it will be difficult to set the operating point. As above, there are applications (e.g., the so-called "dynamic load") where this effect is useful.
- Finally, we can combine them into a more general "golden rule":
- 3. If you want to set precisely the voltage across and current through a non-linear element, drive it by the opposite kind of source.
- > Are there further arguments for publishing the output characteristics for Ib=const and not for Vbe=const.
- Maybe the Earley effect?
- I fully agree with OP considerations about measuring the transistor output curve. We can very easily and precisely set successive current values with constant increment. Thus, the IV curves will be evenly spaced vertically (equidistant from each other).
- Let me generalize these observations into a "golden rule":
- 1. If you want to set precisely the voltage across and current through a voltage-stable non-linear element (diode, base-emitter junction of a transistor), drive it by a current source. Otherwise (if you control it with a voltage source), the current will change rapidly and it will be difficult to set the operating point. It is interesting that, in other applications (such as a differential pair), this effect (aka "current steering") is useful.
- We can formulate also a dual "golden rule":
- 2. If you want to set precisely the voltage across and current through a current-stable non-linear element (collector-emitter junction of a transistor), drive it by a voltage source. Otherwise (if you control it with a current source), the voltage will change rapidly and it will be difficult to set the operating point. As above, there are applications (e.g., the so-called "dynamic load") where this effect is useful.
- Finally, we can combine them into a more general "golden rule":
- 3. If you want to set precisely the voltage across and current through a non-linear element, drive it by the opposite kind of source.
- > Are there further arguments for publishing the output characteristics for Ib=const and not for Vbe=const.
- Maybe the Earley effect?
#1: Initial revision
by
Circuit fantasist
·
2020-10-19T20:14:56Z (about 4 years ago)
I fully agree with OP considerations. We can very easily and precisely set successive current values with constant increment. Thus, the IV curves will be evenly spaced vertically (equidistant from each other). Let me generalize these observations into a "golden rule": 1. If you want to set precisely the voltage across and current through a voltage-stable non-linear element (diode, base-emitter junction of a transistor), drive it by a current source. Otherwise (if you control it with a voltage source), the current will change rapidly and it will be difficult to set the operating point. It is interesting that, in other applications (such as a differential pair), this effect (aka "current steering") is useful. We can formulate also a dual "golden rule": 2. If you want to set precisely the voltage across and current through a current-stable non-linear element (collector-emitter junction of a transistor), drive it by a voltage source. Otherwise (if you control it with a current source), the voltage will change rapidly and it will be difficult to set the operating point. As above, there are applications (e.g., the so-called "dynamic load") where this effect is useful. Finally, we can combine them into a more general "golden rule": 3. If you want to set precisely the voltage across and current through a non-linear element, drive it by the opposite kind of source. > Are there further arguments for publishing the output characteristics for Ib=const and not for Vbe=const. Maybe the Earley effect?