what is the difference between a regular 1n4004 and a glass type 1n4004?
the glass type looks very similar to zener diodes
Thank you
Lawrence
the glass type looks very similar to zener diodes
Thank you
Lawrence
Guessing the glass envelope is pretty early date of manufacturing, OR (or and/or) was made for a military application.
Are you sure it is not a small signal 1N914 type - the newer versions have a different number that is similar to the 1N4004, iirc...?
_-_-
Are you sure it is not a small signal 1N914 type - the newer versions have a different number that is similar to the 1N4004, iirc...?
_-_-
I haaave plastic ones in my stock, but we used to get real 1N4004 in glass years ago. Use either.
The glass package is the earliest and most original package, and (if memory serves) may be rated for operation over a wider temperature range. Plastic packages were phased in starting in the late 1960's.
Dale
Dale
excellent
excellent replys guys....these look exactly like zener diodes and they are labled 1N4004 right on the diode
excellent replys guys....these look exactly like zener diodes and they are labled 1N4004 right on the diode
A power axial diode is a small disc of silicon brazed between two leads. The edge of the silicon is susceptible to ionic contamination, which will degrade the diode reverse leakage. The glass body is applied to the assembled lead and diode as a slurry, dried, then fired. The glass produces a hermetic seal, meaning that there will be no contamination able to get to the junction.
The glass body makes it a bit difficult for automated machinery to auto-insert the diode and have it stay in place, it tends to rock back and forth on the pc board, and can be a problem through a wave soldering operation.
General instrument patented the "super-rectifier", which was a plastic overmolded body applied to a glass body diode. This provided a well molded, completely cylindrical body to the diode, which prevented rocking after insertion.
The molding/encapsulation plastics by themselves are an issue if you exceed the temperature at which the plastic becomes soft. At that point, it expands more than it does at lower temperatures, and can expose the junction to contamination. That is why it is important to not exceed rated temperature/time during soldering.
So the important thing to watch for is the part number, not necessarily a difference of glass vs plastic. There may actually be a glass bead under the hood, so to speak.
jn
The glass body makes it a bit difficult for automated machinery to auto-insert the diode and have it stay in place, it tends to rock back and forth on the pc board, and can be a problem through a wave soldering operation.
General instrument patented the "super-rectifier", which was a plastic overmolded body applied to a glass body diode. This provided a well molded, completely cylindrical body to the diode, which prevented rocking after insertion.
The molding/encapsulation plastics by themselves are an issue if you exceed the temperature at which the plastic becomes soft. At that point, it expands more than it does at lower temperatures, and can expose the junction to contamination. That is why it is important to not exceed rated temperature/time during soldering.
So the important thing to watch for is the part number, not necessarily a difference of glass vs plastic. There may actually be a glass bead under the hood, so to speak.
jn
Thanks again Jn you are very well versed in electronics...do you understand circuits? I have a very excellent non hifi sounding phono i would like to understand how it works nothing like i have seen anywhere...care to look at it for me?
I am very well versed in diodes. For circuits, there are so many others here that can run rings around me. I'm sure if you ask, others will assist.
jn
Suggest you start a new thread, or alternately build or buy one of the boards, semi-kits, or group buys for a phono stage that rampage through this forum from time to time. Many to choose from.
And/or you can post info on the present one in a new thread... that's what I meant by starting a new thread.
And/or you can post info on the present one in a new thread... that's what I meant by starting a new thread.
- Status
- Not open for further replies.