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#41
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Silicon vs. Germanium (was Heil Omega 400 transistors)
http://www.ti.com/corp/docs/company/...oduction.shtml
gives one look at the question - it's a 1954 press release about silicon transistors. Interesting link. I enjoyed the term "triode transistor". They were still thinking in terms of vacuum tubes in those days, weren't they? |
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#42
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Silicon vs. Germanium (was Heil Omega 400 transistors)
http://www.ti.com/corp/docs/company/...oduction.shtml
gives one look at the question - it's a 1954 press release about silicon transistors. Interesting link. I enjoyed the term "triode transistor". They were still thinking in terms of vacuum tubes in those days, weren't they? |
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#43
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Silicon vs. Germanium (was Heil Omega 400 transistors)
http://www.ti.com/corp/docs/company/...oduction.shtml
gives one look at the question - it's a 1954 press release about silicon transistors. Interesting link. I enjoyed the term "triode transistor". They were still thinking in terms of vacuum tubes in those days, weren't they? |
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#44
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Silicon vs. Germanium (was Heil Omega 400 transistors)
On Tue, 06 Jul 2004 02:08:59 GMT, "Karl Uppiano"
wrote: http://www.ti.com/corp/docs/company/...oduction.shtml gives one look at the question - it's a 1954 press release about silicon transistors. Interesting link. I enjoyed the term "triode transistor". They were still thinking in terms of vacuum tubes in those days, weren't they? Nope, they were thinking in terms of correct semantics. A transistor has three electrodes, hence it *is* a triode, just like its vacuum tube predecessor. The term was later dropped because almost all transistors are triodes, hence there isn't the need for additional descriptors thatyou have with vacuum tubes. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
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#45
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Silicon vs. Germanium (was Heil Omega 400 transistors)
On Tue, 06 Jul 2004 02:08:59 GMT, "Karl Uppiano"
wrote: http://www.ti.com/corp/docs/company/...oduction.shtml gives one look at the question - it's a 1954 press release about silicon transistors. Interesting link. I enjoyed the term "triode transistor". They were still thinking in terms of vacuum tubes in those days, weren't they? Nope, they were thinking in terms of correct semantics. A transistor has three electrodes, hence it *is* a triode, just like its vacuum tube predecessor. The term was later dropped because almost all transistors are triodes, hence there isn't the need for additional descriptors thatyou have with vacuum tubes. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
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#46
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Silicon vs. Germanium (was Heil Omega 400 transistors)
On Tue, 06 Jul 2004 02:08:59 GMT, "Karl Uppiano"
wrote: http://www.ti.com/corp/docs/company/...oduction.shtml gives one look at the question - it's a 1954 press release about silicon transistors. Interesting link. I enjoyed the term "triode transistor". They were still thinking in terms of vacuum tubes in those days, weren't they? Nope, they were thinking in terms of correct semantics. A transistor has three electrodes, hence it *is* a triode, just like its vacuum tube predecessor. The term was later dropped because almost all transistors are triodes, hence there isn't the need for additional descriptors thatyou have with vacuum tubes. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
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#47
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Silicon vs. Germanium (was Heil Omega 400 transistors)
On Mon, 05 Jul 2004 18:31:12 GMT, "Karl Uppiano"
wrote: I wonder what it was that made silicon win out over germanium in solid state technology. Back in the '60s, we used to see a lot of germanium transistors. Germanium has a lower p-n drop (0.2 volts vs. 0.6 for silicon) which could theoretically reduce power dissipation. In the late '70s and early '80s, there was a rectifier company that was making germanium rectifiers for power supplies because they were more efficient. So, what are the properties of silicon that make it superior to germanium? Easier to fabricate? More reliable? Higher power/current capability? Less temperature sensitive? cheaper/more plentiful? All of the above! :-) Principally however, it was the max junction temperature of about 200 degrees Celsius, rather than the 85 of germanium, which made the difference. As we used to say in the '60s, geraniums wilt! If you need a high efficiency diode, you'd now use a Schottky, which combines low forward drop with high temperature capability. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
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#48
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Silicon vs. Germanium (was Heil Omega 400 transistors)
On Mon, 05 Jul 2004 18:31:12 GMT, "Karl Uppiano"
wrote: I wonder what it was that made silicon win out over germanium in solid state technology. Back in the '60s, we used to see a lot of germanium transistors. Germanium has a lower p-n drop (0.2 volts vs. 0.6 for silicon) which could theoretically reduce power dissipation. In the late '70s and early '80s, there was a rectifier company that was making germanium rectifiers for power supplies because they were more efficient. So, what are the properties of silicon that make it superior to germanium? Easier to fabricate? More reliable? Higher power/current capability? Less temperature sensitive? cheaper/more plentiful? All of the above! :-) Principally however, it was the max junction temperature of about 200 degrees Celsius, rather than the 85 of germanium, which made the difference. As we used to say in the '60s, geraniums wilt! If you need a high efficiency diode, you'd now use a Schottky, which combines low forward drop with high temperature capability. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
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#49
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Silicon vs. Germanium (was Heil Omega 400 transistors)
On Mon, 05 Jul 2004 18:31:12 GMT, "Karl Uppiano"
wrote: I wonder what it was that made silicon win out over germanium in solid state technology. Back in the '60s, we used to see a lot of germanium transistors. Germanium has a lower p-n drop (0.2 volts vs. 0.6 for silicon) which could theoretically reduce power dissipation. In the late '70s and early '80s, there was a rectifier company that was making germanium rectifiers for power supplies because they were more efficient. So, what are the properties of silicon that make it superior to germanium? Easier to fabricate? More reliable? Higher power/current capability? Less temperature sensitive? cheaper/more plentiful? All of the above! :-) Principally however, it was the max junction temperature of about 200 degrees Celsius, rather than the 85 of germanium, which made the difference. As we used to say in the '60s, geraniums wilt! If you need a high efficiency diode, you'd now use a Schottky, which combines low forward drop with high temperature capability. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
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#50
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Silicon vs. Germanium (was Heil Omega 400 transistors)
"Stewart Pinkerton" wrote in message ... On Tue, 06 Jul 2004 02:08:59 GMT, "Karl Uppiano" wrote: http://www.ti.com/corp/docs/company/...oduction.shtml gives one look at the question - it's a 1954 press release about silicon transistors. Interesting link. I enjoyed the term "triode transistor". They were still thinking in terms of vacuum tubes in those days, weren't they? Nope, they were thinking in terms of correct semantics. A transistor has three electrodes, hence it *is* a triode, just like its vacuum tube predecessor. The term was later dropped because almost all transistors are triodes, hence there isn't the need for additional descriptors thatyou have with vacuum tubes. That's what I was getting at. They hadn't gotten around to realizing yet that transistors were only going to have three legs for the next 50-odd years. Unlike tubes, n-odes weren't going to be much of a distinguishing factor. Once we really got into it, we started referring to them by polarity and type (e.g., NPN vs. PNP, BJT vs. FET, JFET vs. MOSFET, even a short flurry of activity with UJTs, an odd bird that was hyped up all over Electronics Illustrated, but that I don't see much of any more). I have only seen a few dual-gate MOSFETS, which were four-terminal devices (tetrodes, I guess), used as multipliers in superhet detectors. Oh, and those dual-emitter things used in TTL logic gates. |
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#51
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Silicon vs. Germanium (was Heil Omega 400 transistors)
"Stewart Pinkerton" wrote in message ... On Tue, 06 Jul 2004 02:08:59 GMT, "Karl Uppiano" wrote: http://www.ti.com/corp/docs/company/...oduction.shtml gives one look at the question - it's a 1954 press release about silicon transistors. Interesting link. I enjoyed the term "triode transistor". They were still thinking in terms of vacuum tubes in those days, weren't they? Nope, they were thinking in terms of correct semantics. A transistor has three electrodes, hence it *is* a triode, just like its vacuum tube predecessor. The term was later dropped because almost all transistors are triodes, hence there isn't the need for additional descriptors thatyou have with vacuum tubes. That's what I was getting at. They hadn't gotten around to realizing yet that transistors were only going to have three legs for the next 50-odd years. Unlike tubes, n-odes weren't going to be much of a distinguishing factor. Once we really got into it, we started referring to them by polarity and type (e.g., NPN vs. PNP, BJT vs. FET, JFET vs. MOSFET, even a short flurry of activity with UJTs, an odd bird that was hyped up all over Electronics Illustrated, but that I don't see much of any more). I have only seen a few dual-gate MOSFETS, which were four-terminal devices (tetrodes, I guess), used as multipliers in superhet detectors. Oh, and those dual-emitter things used in TTL logic gates. |
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#52
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Silicon vs. Germanium (was Heil Omega 400 transistors)
"Stewart Pinkerton" wrote in message ... On Tue, 06 Jul 2004 02:08:59 GMT, "Karl Uppiano" wrote: http://www.ti.com/corp/docs/company/...oduction.shtml gives one look at the question - it's a 1954 press release about silicon transistors. Interesting link. I enjoyed the term "triode transistor". They were still thinking in terms of vacuum tubes in those days, weren't they? Nope, they were thinking in terms of correct semantics. A transistor has three electrodes, hence it *is* a triode, just like its vacuum tube predecessor. The term was later dropped because almost all transistors are triodes, hence there isn't the need for additional descriptors thatyou have with vacuum tubes. That's what I was getting at. They hadn't gotten around to realizing yet that transistors were only going to have three legs for the next 50-odd years. Unlike tubes, n-odes weren't going to be much of a distinguishing factor. Once we really got into it, we started referring to them by polarity and type (e.g., NPN vs. PNP, BJT vs. FET, JFET vs. MOSFET, even a short flurry of activity with UJTs, an odd bird that was hyped up all over Electronics Illustrated, but that I don't see much of any more). I have only seen a few dual-gate MOSFETS, which were four-terminal devices (tetrodes, I guess), used as multipliers in superhet detectors. Oh, and those dual-emitter things used in TTL logic gates. |
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#53
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Silicon vs. Germanium (was Heil Omega 400 transistors)
On Tue, 06 Jul 2004 08:18:12 GMT, "Karl Uppiano"
wrote: "Stewart Pinkerton" wrote in message .. . On Tue, 06 Jul 2004 02:08:59 GMT, "Karl Uppiano" wrote: http://www.ti.com/corp/docs/company/...oduction.shtml gives one look at the question - it's a 1954 press release about silicon transistors. Interesting link. I enjoyed the term "triode transistor". They were still thinking in terms of vacuum tubes in those days, weren't they? Nope, they were thinking in terms of correct semantics. A transistor has three electrodes, hence it *is* a triode, just like its vacuum tube predecessor. The term was later dropped because almost all transistors are triodes, hence there isn't the need for additional descriptors thatyou have with vacuum tubes. That's what I was getting at. They hadn't gotten around to realizing yet that transistors were only going to have three legs for the next 50-odd years. Unlike tubes, n-odes weren't going to be much of a distinguishing factor. Once we really got into it, we started referring to them by polarity and type (e.g., NPN vs. PNP, BJT vs. FET, JFET vs. MOSFET, even a short flurry of activity with UJTs, an odd bird that was hyped up all over Electronics Illustrated, but that I don't see much of any more). I have only seen a few dual-gate MOSFETS, which were four-terminal devices (tetrodes, I guess), used as multipliers in superhet detectors. Oh, and those dual-emitter things used in TTL logic gates. This is all good stuff apart from the tetrode comparison. In fact a JFET is a pretty good match for a tetrode - it just doesn't need the fourth terminal, which in the tetrode is really for mopping up lost electrons that otherwise float around under certain anode voltage conditions. d Pearce Consulting http://www.pearce.uk.com |
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#54
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Silicon vs. Germanium (was Heil Omega 400 transistors)
On Tue, 06 Jul 2004 08:18:12 GMT, "Karl Uppiano"
wrote: "Stewart Pinkerton" wrote in message .. . On Tue, 06 Jul 2004 02:08:59 GMT, "Karl Uppiano" wrote: http://www.ti.com/corp/docs/company/...oduction.shtml gives one look at the question - it's a 1954 press release about silicon transistors. Interesting link. I enjoyed the term "triode transistor". They were still thinking in terms of vacuum tubes in those days, weren't they? Nope, they were thinking in terms of correct semantics. A transistor has three electrodes, hence it *is* a triode, just like its vacuum tube predecessor. The term was later dropped because almost all transistors are triodes, hence there isn't the need for additional descriptors thatyou have with vacuum tubes. That's what I was getting at. They hadn't gotten around to realizing yet that transistors were only going to have three legs for the next 50-odd years. Unlike tubes, n-odes weren't going to be much of a distinguishing factor. Once we really got into it, we started referring to them by polarity and type (e.g., NPN vs. PNP, BJT vs. FET, JFET vs. MOSFET, even a short flurry of activity with UJTs, an odd bird that was hyped up all over Electronics Illustrated, but that I don't see much of any more). I have only seen a few dual-gate MOSFETS, which were four-terminal devices (tetrodes, I guess), used as multipliers in superhet detectors. Oh, and those dual-emitter things used in TTL logic gates. This is all good stuff apart from the tetrode comparison. In fact a JFET is a pretty good match for a tetrode - it just doesn't need the fourth terminal, which in the tetrode is really for mopping up lost electrons that otherwise float around under certain anode voltage conditions. d Pearce Consulting http://www.pearce.uk.com |
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#55
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Silicon vs. Germanium (was Heil Omega 400 transistors)
On Tue, 06 Jul 2004 08:18:12 GMT, "Karl Uppiano"
wrote: "Stewart Pinkerton" wrote in message .. . On Tue, 06 Jul 2004 02:08:59 GMT, "Karl Uppiano" wrote: http://www.ti.com/corp/docs/company/...oduction.shtml gives one look at the question - it's a 1954 press release about silicon transistors. Interesting link. I enjoyed the term "triode transistor". They were still thinking in terms of vacuum tubes in those days, weren't they? Nope, they were thinking in terms of correct semantics. A transistor has three electrodes, hence it *is* a triode, just like its vacuum tube predecessor. The term was later dropped because almost all transistors are triodes, hence there isn't the need for additional descriptors thatyou have with vacuum tubes. That's what I was getting at. They hadn't gotten around to realizing yet that transistors were only going to have three legs for the next 50-odd years. Unlike tubes, n-odes weren't going to be much of a distinguishing factor. Once we really got into it, we started referring to them by polarity and type (e.g., NPN vs. PNP, BJT vs. FET, JFET vs. MOSFET, even a short flurry of activity with UJTs, an odd bird that was hyped up all over Electronics Illustrated, but that I don't see much of any more). I have only seen a few dual-gate MOSFETS, which were four-terminal devices (tetrodes, I guess), used as multipliers in superhet detectors. Oh, and those dual-emitter things used in TTL logic gates. This is all good stuff apart from the tetrode comparison. In fact a JFET is a pretty good match for a tetrode - it just doesn't need the fourth terminal, which in the tetrode is really for mopping up lost electrons that otherwise float around under certain anode voltage conditions. d Pearce Consulting http://www.pearce.uk.com |
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#56
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Silicon vs. Germanium (was Heil Omega 400 transistors)
"Don Pearce" wrote in message ... On Tue, 06 Jul 2004 08:18:12 GMT, "Karl Uppiano" wrote: "Stewart Pinkerton" wrote in message .. . On Tue, 06 Jul 2004 02:08:59 GMT, "Karl Uppiano" wrote: http://www.ti.com/corp/docs/company/...oduction.shtml gives one look at the question - it's a 1954 press release about silicon transistors. Interesting link. I enjoyed the term "triode transistor". They were still thinking in terms of vacuum tubes in those days, weren't they? Nope, they were thinking in terms of correct semantics. A transistor has three electrodes, hence it *is* a triode, just like its vacuum tube predecessor. The term was later dropped because almost all transistors are triodes, hence there isn't the need for additional descriptors thatyou have with vacuum tubes. That's what I was getting at. They hadn't gotten around to realizing yet that transistors were only going to have three legs for the next 50-odd years. Unlike tubes, n-odes weren't going to be much of a distinguishing factor. Once we really got into it, we started referring to them by polarity and type (e.g., NPN vs. PNP, BJT vs. FET, JFET vs. MOSFET, even a short flurry of activity with UJTs, an odd bird that was hyped up all over Electronics Illustrated, but that I don't see much of any more). I have only seen a few dual-gate MOSFETS, which were four-terminal devices (tetrodes, I guess), used as multipliers in superhet detectors. Oh, and those dual-emitter things used in TTL logic gates. This is all good stuff apart from the tetrode comparison. In fact a JFET is a pretty good match for a tetrode - it just doesn't need the fourth terminal, which in the tetrode is really for mopping up lost electrons that otherwise float around under certain anode voltage conditions. d Pearce Consulting http://www.pearce.uk.com I agree JFETs are 3-terminal devices that have tetrode tube-like characteristics, but tetra means four, which is where the tube got it's name. So it depends if you go by behavior or by semantics. What to choose, what to choose... |
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#57
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Silicon vs. Germanium (was Heil Omega 400 transistors)
"Don Pearce" wrote in message ... On Tue, 06 Jul 2004 08:18:12 GMT, "Karl Uppiano" wrote: "Stewart Pinkerton" wrote in message .. . On Tue, 06 Jul 2004 02:08:59 GMT, "Karl Uppiano" wrote: http://www.ti.com/corp/docs/company/...oduction.shtml gives one look at the question - it's a 1954 press release about silicon transistors. Interesting link. I enjoyed the term "triode transistor". They were still thinking in terms of vacuum tubes in those days, weren't they? Nope, they were thinking in terms of correct semantics. A transistor has three electrodes, hence it *is* a triode, just like its vacuum tube predecessor. The term was later dropped because almost all transistors are triodes, hence there isn't the need for additional descriptors thatyou have with vacuum tubes. That's what I was getting at. They hadn't gotten around to realizing yet that transistors were only going to have three legs for the next 50-odd years. Unlike tubes, n-odes weren't going to be much of a distinguishing factor. Once we really got into it, we started referring to them by polarity and type (e.g., NPN vs. PNP, BJT vs. FET, JFET vs. MOSFET, even a short flurry of activity with UJTs, an odd bird that was hyped up all over Electronics Illustrated, but that I don't see much of any more). I have only seen a few dual-gate MOSFETS, which were four-terminal devices (tetrodes, I guess), used as multipliers in superhet detectors. Oh, and those dual-emitter things used in TTL logic gates. This is all good stuff apart from the tetrode comparison. In fact a JFET is a pretty good match for a tetrode - it just doesn't need the fourth terminal, which in the tetrode is really for mopping up lost electrons that otherwise float around under certain anode voltage conditions. d Pearce Consulting http://www.pearce.uk.com I agree JFETs are 3-terminal devices that have tetrode tube-like characteristics, but tetra means four, which is where the tube got it's name. So it depends if you go by behavior or by semantics. What to choose, what to choose... |
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#58
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Silicon vs. Germanium (was Heil Omega 400 transistors)
"Don Pearce" wrote in message ... On Tue, 06 Jul 2004 08:18:12 GMT, "Karl Uppiano" wrote: "Stewart Pinkerton" wrote in message .. . On Tue, 06 Jul 2004 02:08:59 GMT, "Karl Uppiano" wrote: http://www.ti.com/corp/docs/company/...oduction.shtml gives one look at the question - it's a 1954 press release about silicon transistors. Interesting link. I enjoyed the term "triode transistor". They were still thinking in terms of vacuum tubes in those days, weren't they? Nope, they were thinking in terms of correct semantics. A transistor has three electrodes, hence it *is* a triode, just like its vacuum tube predecessor. The term was later dropped because almost all transistors are triodes, hence there isn't the need for additional descriptors thatyou have with vacuum tubes. That's what I was getting at. They hadn't gotten around to realizing yet that transistors were only going to have three legs for the next 50-odd years. Unlike tubes, n-odes weren't going to be much of a distinguishing factor. Once we really got into it, we started referring to them by polarity and type (e.g., NPN vs. PNP, BJT vs. FET, JFET vs. MOSFET, even a short flurry of activity with UJTs, an odd bird that was hyped up all over Electronics Illustrated, but that I don't see much of any more). I have only seen a few dual-gate MOSFETS, which were four-terminal devices (tetrodes, I guess), used as multipliers in superhet detectors. Oh, and those dual-emitter things used in TTL logic gates. This is all good stuff apart from the tetrode comparison. In fact a JFET is a pretty good match for a tetrode - it just doesn't need the fourth terminal, which in the tetrode is really for mopping up lost electrons that otherwise float around under certain anode voltage conditions. d Pearce Consulting http://www.pearce.uk.com I agree JFETs are 3-terminal devices that have tetrode tube-like characteristics, but tetra means four, which is where the tube got it's name. So it depends if you go by behavior or by semantics. What to choose, what to choose... |
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#59
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Silicon vs. Germanium (was Heil Omega 400 transistors)
On Tue, 06 Jul 2004 08:18:12 GMT, Karl Uppiano wrote:
Once we really got into it, we started referring to them by polarity and type (e.g., NPN vs. PNP, BJT vs. FET, JFET vs. MOSFET, even a short flurry of activity with UJTs, an odd bird that was hyped up all over Electronics Illustrated, but that I don't see much of any more). I have only seen a few dual-gate MOSFETS, which were four-terminal devices (tetrodes, I guess), used as multipliers in superhet detectors. Oh, and those dual-emitter things used in TTL logic gates. In the integrated-circuit world, multiple emitter and multiple collector devices are very common (especially in older processes), since it's so easy to make them. I used to regularly build devices with five or six emitters or collectors. Functionally, multiple emitter/collector devices are generally the same as the same number of individual transistors in parallel, but the combined device often takes considerably less space on an IC. -- Mike -- |
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#60
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Silicon vs. Germanium (was Heil Omega 400 transistors)
In article ,
Mike wrote: In the integrated-circuit world, multiple emitter and multiple collector devices are very common (especially in older processes), since it's so easy to make them. I used to regularly build devices with five or six emitters or collectors. Functionally, multiple emitter/collector devices are generally the same as the same number of individual transistors in parallel, but the combined device often takes considerably less space on an IC. Multiple-emitter transistors, with built-in ballast resistors connected to each emitter, are also used for RF applications. The parallelism and internal ballasting make the transistors quite a bit more rugged, and able to survive heavy or mismatched loads (e.g. shorted or open outputs) than would be the case for a single-emitter transistor having the same current-drive capacity. -- Dave Platt AE6EO Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
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