I can post dozens of exceptions to that rule.If it is a discrete device then it goes inside a circle.
I can post dozens of exceptions to that rule.If it is a discrete device then it goes inside a circle.
I draw schematics in a way it would look most pleasing to the viewer.So If I have a bunch of connections going around the transistor then I would make sure it gets noticed,so I would just a draw a circle around it or a dashed box.
To this day; I'd call that a pseudo-standard symbol.I recall seen the dashed box for transistors requiring heat sink.
I never heard about it,I'm pretty sure that there is no official heat sink symbol.I recall seen the dashed box for transistors requiring heat sink.
And that is where I was headed with this. I am of retirement age, which means that the majority of EE, techs, hobbiests, etc. in the US are younger than me, which means that a large, but decreasing, subset grew up reading Popular Electronics, the RCA and GE manuals, etc., and we all had a common baseline exposure to how the pro's did it. The two reference magazines, PE and Electronics World, both circled semiconductors, including specialty diodes like zeners and tunnels. Clearly that has changed over the years for BJTs and diodes, but not so consistantly for JFETs, and even less so for MOSFETs. In college there was no course in schematic drawing, and it never was addressed specifically in classes. The textbooks had small schematics, never anything large or complex, and the assumption was that everyone in electronics at that level already just sorta knew.An RCA manual, dated 1971, shows BJTs, FETs and diodes with a circle.
Agree. It isn't an electronic component, but it is something that needs to be a controlled aspect of the design. Like mounting holes, fiducials, etc.I never heard about it,I'm pretty sure that there is no official heat sink symbol.
So can I. Doesn't mean anything. I can post dozens of examples of engineers violating the rules of spelling and grammar, too. This isn't even a rule, anyway, or even a guideline. Really just a convention or a trend. I'm just stating there is a logical reason why the circles around devices started going away in the 60s and 70s, even if engineers at the time weren't aware they were doing it. And for any given convention, not everyone is going to follow it. At least not until the Cadence and Mentor standard libraries for IC process transistors come out sans circles. Then we all follow it.I can post dozens of exceptions to that rule.
Because they are not discrete transistors. He never said resistors, capacitors and all other discrete components had circles.And yet opamps and NAND gates never have circles around them.
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Yeah, but that sorta makes sense since is is very common for those circuits use two separate devices. If you follow that logic, it makes sense to circle a power MOSFET because of the included zener diode.I'm going to still offer as evidence for what I'm claiming the fact that darlingtons and matched pairs are usually drawn inside a circle or oval enclosing both transistors.
That brings up a very good point. Darlington transistors in a single package should probably be drawn with a circle as well. Otherwise it may look like two separate transistors, which may have different specs than a packaged Darlington pair.I am fine for the most part with leaving the circles off, and telling those entering the field such is preferred but not demanded for "reasons of history."
The exception to this is the modern trend to stuff more stuff into SMD packages, such as "pre-biased" transistors where resistors (series base and/or base to emitter) are included in the device. When I draw these I include the resistors in the symbol and then box it, either solid or dashed lines, so both the schematic and package properties are both clear.
That reminds me of one of my stories: I was working for a hybrid company that won a bid for a power device in a TO-3 package, two transistors with a small cap and perhaps a resistor or such. I got the package after we won a gov't contract to make these obsolete devices. As I reviewed the package something seemed familiar. I cracked up a Motorola data book and found our spec was written around a Motorola data sheet for a darlington device. (The cap was paralytic.)That brings up a very good point. Darlington transistors in a single package should probably be drawn with a circle as well. Otherwise it may look like two separate transistors, which may have different specs than a packaged Darlington pair.