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Re: Some observations on linear power supplies
Microsemi became Microchips and changed the numbers on all their technical documents, I'm too busy tonight to find the correct paper. Basically when a diode is reverse biased and goes from conducting
By wn4isx <wn4isx@...> · #99683 ·
Re: Some observations on linear power supplies
The only thing that made sense about Astron supplies is they sure made/make money. For overvoltage protection?I'd use something like the one shown in https://axotron.se/index_en.php?page=26 I'd place
By wn4isx <wn4isx@...> · #99682 ·
Re: Some observations on linear power supplies
I've seen some stuff out there that puts a cap across rectifier diodes, sometimes just two out of the four, not sure why they'd do that. I also used to see a cap across the AC line, or a
By Roy J. Tellason, Sr. · #99681 ·
Re: Some observations on linear power supplies
That crowbar circuit in the referenced pdf didn't make a whole lot of sense to me. Not that I examined it that closely, it's approaching the limit for what I can see on this monitor. But do you need
By Roy J. Tellason, Sr. · #99680 ·
Re: Some observations on linear power supplies
I last messed with the 723 somewhere in the early 1970s. I'm guessing that this was before the common 3-terminal regulator parts were pretty much everywhere. I have very little reason to consider
By Roy J. Tellason, Sr. · #99679 ·
Re: Some observations on linear power supplies
Note 3 should read Add a 0.01uF capacitor with a 27~33 ohm resistor in series across each power rectifier to minimize commutation EMI [radio noise]. I have a nice PDF on diode commutation noise and
By wn4isx <wn4isx@...> · #99678 ·
Some observations on linear power supplies
First I consider Astron power supplies to be over rated and exist only because "hams have always used them." I'm amazed [really more dismayed] they get decent reviews. There are too many deficiencies
By wn4isx <wn4isx@...> · #99677 ·
A "magic" antenna
When a member of our shortwave listener club showed me a PA0RDT active E-Probe antenna I almost giggled, being polite I didn't giggle. However I thought "Well PT Barnum was right...one is born every
By wn4isx <wn4isx@...> · #99676 ·
Re: I found a stash of 5 'new old stock' 5CP1 5 inch oscilloscope CRT
Re: " Honda stock electrics sucked almost as bad as Lucas." I've never been able to understand the original stock Honda 350/360 charge system. It appeared to be a SCR that shorted out the V+ after a
By wn4isx <wn4isx@...> · #99675 ·
Re: I found a stash of 5 'new old stock' 5CP1 5 inch oscilloscope CRT
An interesting read, that. I've been pretty lucky, the closest I've come to that kind of an encounter is the other end of the town where I lived before I moved over here. That, and one other occasion
By Roy J. Tellason, Sr. · #99674 ·
Re: I found a stash of 5 'new old stock' 5CP1 5 inch oscilloscope CRT
I'm really a shortwave listener who happened to pick up his ham license. https://en.wikipedia.org/wiki/1974_Super_Outbreak That nightmare convinced me ham radio had a use. I rode a Honda CB350 with a
By wn4isx <wn4isx@...> · #99673 ·
Re: I found a stash of 5 'new old stock' 5CP1 5 inch oscilloscope CRT
I remember seeing them mentioned a fair amount back when, not so much lately. I can believe that.
By Roy J. Tellason, Sr. · #99672 ·
Re: I found a stash of 5 'new old stock' 5CP1 5 inch oscilloscope CRT
At one time 88mH (and other value) inductors were as common as roaches and just about as valuable. Today they are scarce, a quick net search didn't find any 'real' 88mH loading coils for sale. RTTY is
By wn4isx <wn4isx@...> · #99671 ·
Re: I found a stash of 5 'new old stock' 5CP1 5 inch oscilloscope CRT
I've heard of those things for a really long time. Seen them referenced in magazines, etc. But I don't think that I've ever actually run across them... I do have some toroid coils, no idea what
By Roy J. Tellason, Sr. · #99670 ·
Electronics Index
All sorts of stuff: https://mysite.du.edu/~etuttle/electron/elecindx.htm -- Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, ?a
By Roy J. Tellason, Sr. · #99669 ·
Re: I found a stash of 5 'new old stock' 5CP1 5 inch oscilloscope CRT
I have several software programs that emulate the old CRT mark/space vertical/horizontal? display with a simulation on the PC screen. It isn't as accurate as the CRT display, I'd say it's about 60%
By wn4isx <wn4isx@...> · #99668 ·
Re: I found a stash of 5 'new old stock' 5CP1 5 inch oscilloscope CRT
Heh. I remember seeing a setup like that. This was so long ago that I can't even remember when it was. Somebody I knew thought that I might perhaps be interested in ham radio, and introduced me to
By Roy J. Tellason, Sr. · #99667 ·
I found a stash of 5 'new old stock' 5CP1 5 inch oscilloscope CRT
I found a stash of 5 'new old stock' 5CP1 5 inch oscilloscope CRTs at my parent's home. The new owners called my sister and told her they found a box of "electrical junk" under the eves. I went over,
By wn4isx <wn4isx@...> · #99666 ·
Re: What is sidereal time? Why is it used? And How to make it?
The published charts/formula for delay are all wrong, or 'wrong' for certain manufacturers CMOS 555's.. I spent several hours cut and pasting RC values to get the time delay I needed. All 555 are not
By wn4isx <wn4isx@...> · #99665 ·
Re: What is sidereal time? Why is it used? And How to make it?
How so? -- Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, ?a critter that can be killed but can't be tamed. ?--Robert A.
By Roy J. Tellason, Sr. · #99664 ·