AeroElectric-List Digest Archive

Wed 06/25/08


Total Messages Posted: 11



Today's Message Index:
----------------------
 
     1. 04:39 AM - Re: Need a to-220 connector (ROGER & JEAN CURTIS)
     2. 05:13 AM - Re: Need a to-220 connector (Rob Turk)
     3. 05:26 AM - Re: Need a to-220 connector (Robert L. Nuckolls, III)
     4. 06:38 AM - Re: Need a to-220 connector (Alan Adamson)
     5. 07:56 AM - 90-deg. Crimp BNC Connectors (Jim Piavis)
     6. 02:19 PM - Re: Need a to-220 connector (rampil)
     7. 02:20 PM - Re: 90-deg. Crimp BNC Connectors (rampil)
     8. 04:00 PM - Re: Re: Need a to-220 connector (Alan Adamson)
     9. 05:44 PM - Re: Re: Need a to-220 connector (Richard Tasker)
    10. 07:50 PM - Re: Need a to-220 connector (Robert L. Nuckolls, III)
    11. 07:50 PM - off line for a few days . . . (Robert L. Nuckolls, III)
 
 
 


Message 1


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    Time: 04:39:14 AM PST US
    From: "ROGER & JEAN CURTIS" <mrspudandcompany@verizon.net>
    Subject: Need a to-220 connector
    Alan, Looks like an excellent way to connect, I would do it that way. You are essentially putting a square pin (LM7812) into a round hole, but, the "smidge of snugness" will give you a good secure connection. If, at a later date, say 20 years from now, you have a problem with it, you still have the option of solder. Roger -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Alan K. Adamson Sent: Tuesday, June 24, 2008 9:19 PM Subject: AeroElectric-List: Need a to-220 connector <aadamson@highrf.com> Bob, etc all. I need to use to TO-220 LM7812C as a simple voltage regulator to take 24V to 12V for a Bob Archer Antenna switch. No problems with the circuit, the current is small enough (<10ma) that I don't need any additional parts or heatshrink. But I did want to make it such that I could replace the lm7812 without having to solder and unsolder.... Yes I could solder and connector the who regulator, but I thot... Hmm, wonder if the legs of the to-220 part would fit in regular DB25 female pins and yep, they do, pretty much like the male pin would with just a smidge of snugness (new word btw)... If I use heatshrink to keep this all together, does anyone see any issue with using these 3 pins as a simple "to-220 socket"? I'd crimp up the wires to the 3 db25 pins, heatshrink them full length, then slide them on the to-220 and heatshrink it as a unit to the 3 pin wires. Tuck it away and hope I never have to deal with it, but if I do, cut some heatshrink, replace the lm7812 and re-heatshrink. Let me know your thots please... Thanks, Alan Adamson Atlanta, GA


    Message 2


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    Time: 05:13:34 AM PST US
    From: "Rob Turk" <matronics@rtist.nl>
    Subject: Re: Need a to-220 connector
    In general I'd not use a connector at all for this purpose. But if you want to have a connector for this, why not use a 3-pin connector with the same pin distance? Check out those 3-pin connectors that you find on computer fans. They are designed to take flat pins and take a lot less space. Do try to find a good quality connector for this so it doesn't develop problems with corrosion. Especially the ground pin is critical, if it loses contact your switch will get 24V direct. Rob ----- Original Message ----- From: "Alan K. Adamson" <aadamson@highrf.com> Sent: Wednesday, June 25, 2008 3:18 AM Subject: AeroElectric-List: Need a to-220 connector > <aadamson@highrf.com> > > Bob, etc all. > > I need to use to TO-220 LM7812C as a simple voltage regulator to take 24V > to > 12V for a Bob Archer Antenna switch. > > No problems with the circuit, the current is small enough (<10ma) that I > don't need any additional parts or heatshrink. But I did want to make it > such that I could replace the lm7812 without having to solder and > unsolder.... Yes I could solder and connector the who regulator, but I > thot... Hmm, wonder if the legs of the to-220 part would fit in regular > DB25 > female pins and yep, they do, pretty much like the male pin would with > just > a smidge of snugness (new word btw)... > > If I use heatshrink to keep this all together, does anyone see any issue > with using these 3 pins as a simple "to-220 socket"? I'd crimp up the > wires > to the 3 db25 pins, heatshrink them full length, then slide them on the > to-220 and heatshrink it as a unit to the 3 pin wires. Tuck it away and > hope I never have to deal with it, but if I do, cut some heatshrink, > replace > the lm7812 and re-heatshrink. > > Let me know your thots please... > > Thanks, > Alan Adamson > Atlanta, GA > > >


    Message 3


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    Time: 05:26:41 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@cox.net>
    Subject: Re: Need a to-220 connector
    At 09:18 PM 6/24/2008 -0400, you wrote: ><aadamson@highrf.com> > >Bob, etc all. > >I need to use to TO-220 LM7812C as a simple voltage regulator to take 24V to >12V for a Bob Archer Antenna switch. > >No problems with the circuit, the current is small enough (<10ma) that I >don't need any additional parts or heatshrink. But I did want to make it >such that I could replace the lm7812 without having to solder and >unsolder.... Yes I could solder and connector the who regulator, but I >thot... Hmm, wonder if the legs of the to-220 part would fit in regular DB25 >female pins and yep, they do, pretty much like the male pin would with just >a smidge of snugness (new word btw)... Hmmmm . . . the LM7812 series devices are not guaranteed "stable" without a couple of capacitors from input and output to ground. >If I use heatshrink to keep this all together, does anyone see any issue >with using these 3 pins as a simple "to-220 socket"? I'd crimp up the wires >to the 3 db25 pins, heatshrink them full length, then slide them on the >to-220 and heatshrink it as a unit to the 3 pin wires. Tuck it away and >hope I never have to deal with it, but if I do, cut some heatshrink, replace >the lm7812 and re-heatshrink. > >Let me know your thots please... For such a tiny amount of current, how about wiring a 1N4742 zener in series with the switch. Doesn't need capacitors. You can splice the zener into the switch's feed-wire with techniques illustrated in . . . http://aeroelectric.com/articles/Homeless/Homeless_Components.htm Bob . . . ----------------------------------------) ( . . . a long habit of not thinking ) ( a thing wrong, gives it a superficial ) ( appearance of being right . . . ) ( ) ( -Thomas Paine 1776- ) ----------------------------------------


    Message 4


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    Time: 06:38:53 AM PST US
    From: "Alan Adamson" <aadamson@highrf.com>
    Subject: Need a to-220 connector
    Thanks all for the comments, the one about the computer fans is an especially good one... Ok, now I need a bit of an education... Bob, the Zener, will that step the voltage down from 24v to 12v? That's all I really need is a reliable 12V out of 24v. The data sheet on the LM7812C suggested that it didn't need any other components, but I'm always open to better solutions and if the Zener will do it, then I'm all for that. Thanks Alan -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Sent: Wednesday, June 25, 2008 8:21 AM Subject: Re: AeroElectric-List: Need a to-220 connector --> <nuckolls.bob@cox.net> At 09:18 PM 6/24/2008 -0400, you wrote: ><aadamson@highrf.com> > >Bob, etc all. > >I need to use to TO-220 LM7812C as a simple voltage regulator to take >24V to 12V for a Bob Archer Antenna switch. > >No problems with the circuit, the current is small enough (<10ma) that >I don't need any additional parts or heatshrink. But I did want to >make it such that I could replace the lm7812 without having to solder >and unsolder.... Yes I could solder and connector the who regulator, >but I thot... Hmm, wonder if the legs of the to-220 part would fit in >regular DB25 female pins and yep, they do, pretty much like the male >pin would with just a smidge of snugness (new word btw)... Hmmmm . . . the LM7812 series devices are not guaranteed "stable" without a couple of capacitors from input and output to ground. >If I use heatshrink to keep this all together, does anyone see any >issue with using these 3 pins as a simple "to-220 socket"? I'd crimp >up the wires to the 3 db25 pins, heatshrink them full length, then >slide them on the to-220 and heatshrink it as a unit to the 3 pin >wires. Tuck it away and hope I never have to deal with it, but if I >do, cut some heatshrink, replace the lm7812 and re-heatshrink. > >Let me know your thots please... For such a tiny amount of current, how about wiring a 1N4742 zener in series with the switch. Doesn't need capacitors. You can splice the zener into the switch's feed-wire with techniques illustrated in . . . http://aeroelectric.com/articles/Homeless/Homeless_Components.htm Bob . . . ----------------------------------------) ( . . . a long habit of not thinking ) ( a thing wrong, gives it a superficial ) ( appearance of being right . . . ) ( ) ( -Thomas Paine 1776- ) ----------------------------------------


    Message 5


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    Time: 07:56:33 AM PST US
    From: Jim Piavis <jpiavis@microsoft.com>
    Subject: 90-deg. Crimp BNC Connectors
    What's the correct way to crimp the 90-degree BNC connectors? I'm not refer encing the 90-deg. type that requires soldering, but the crimps. I need to install a couple and just want to make sure I'm doing it right. The straigh t ones are no problem but the 90's a bit different. Thanks, Jim


    Message 6


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    Time: 02:19:33 PM PST US
    Subject: Re: Need a to-220 connector
    From: "rampil" <ira.rampil@gmail.com>
    Another connector solution is to use quality connector machined crimp pins on the three leads with mating gender crimp pins on the wiring. Very thin heat shrink on the bare leads and exposed wires. Heat shrink over the mated connections, then a wide piece over the regulator and the whole set of connections. I agree with Bob regarding the stability (e.g. oscillations) of the 78/7900 family without the input bypass cap and the output filter cap. Are you very sure that the Archer thingy will object to 24V? If you have not done so, try calling them to find out. I'm not an EE, I just played one through 4 years of grad school :-) -------- Ira N224XS Read this topic online here: http://forums.matronics.com/viewtopic.php?p=189805#189805


    Message 7


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    Time: 02:20:39 PM PST US
    Subject: Re: 90-deg. Crimp BNC Connectors
    From: "rampil" <ira.rampil@gmail.com>
    You can download the exact directions with pictures and strip lengths from most connector manufacturers. The strip lengths may vary depending on the coax you use. -------- Ira N224XS Read this topic online here: http://forums.matronics.com/viewtopic.php?p=189806#189806


    Message 8


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    Time: 04:00:08 PM PST US
    From: "Alan Adamson" <aadamson@highrf.com>
    Subject: Re: Need a to-220 connector
    Yep, I'm sure, the TR switch won't work with 24v, it's got relays that switch when the intercomm says one radio or the other is active. I picked up the Zener as mentioned, but I'm still unclear, it's it just in series with the switch, in the 24V line and it magically limits (drops) the voltage to 12v? What a great solution for small current needs if that assumption is true. The Zeners that I have are good to 1A, what is the max current you could expect one to operate as a voltage limiter (regulator) I might have one other item that could use the same thing, but I think it draws more like 500mils Alan -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of rampil Sent: Wednesday, June 25, 2008 5:16 PM Subject: AeroElectric-List: Re: Need a to-220 connector Another connector solution is to use quality connector machined crimp pins on the three leads with mating gender crimp pins on the wiring. Very thin heat shrink on the bare leads and exposed wires. Heat shrink over the mated connections, then a wide piece over the regulator and the whole set of connections. I agree with Bob regarding the stability (e.g. oscillations) of the 78/7900 family without the input bypass cap and the output filter cap. Are you very sure that the Archer thingy will object to 24V? If you have not done so, try calling them to find out. I'm not an EE, I just played one through 4 years of grad school :-) -------- Ira N224XS Read this topic online here: http://forums.matronics.com/viewtopic.php?p=189805#189805


    Message 9


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    Time: 05:44:46 PM PST US
    From: Richard Tasker <retasker@optonline.net>
    Subject: Re: Need a to-220 connector
    The zener does NOT drop 24V to 12V. It subtracts whatever the zener rating is from whatever the higher voltage is. If you truly have 24V (more likely 28V if the "24V" is the alternator supply), then it would work fine. However, if the situation is that you have a 28V supply from your alternator, then the zener will subtract from that and you will have not 12V but 16V - possibly outside of the allowable tolerance of the TR switch. The LM7812 does need capacitors for stability, but will supply 12 regardless of the input voltage (until you exceed its ratings). You could use the zener Bob suggests in a slightly different way to get the 12V you want. If you truly need less than 10mA, you can use a resistor in series with a 12V (1N4742) zener and tap off the voltage you need across the 12V zener. Use a 620 ohm, 0.5W (or greater) resistor. This wastes about 10mA more than if you used an LM7812, but there is no need for capacitors. Crude schematic follows (use fixed with font to see it): 24V ----RRRR-------ZZZZ---- GND | |< | 12V GND | | To TR Switch By the way, if you do decide to use an LM7812, I wouldn't worry about soldering it in. With the minimal load you will be drawing, I suspect it will still be going strong long after your plane turns to dust... Dick Tasker Alan Adamson wrote: > > Yep, I'm sure, the TR switch won't work with 24v, it's got relays that > switch when the intercomm says one radio or the other is active. > > I picked up the Zener as mentioned, but I'm still unclear, it's it just in > series with the switch, in the 24V line and it magically limits (drops) the > voltage to 12v? What a great solution for small current needs if that > assumption is true. The Zeners that I have are good to 1A, what is the max > current you could expect one to operate as a voltage limiter (regulator) I > might have one other item that could use the same thing, but I think it > draws more like 500mils > > Alan > > -----Original Message----- > From: owner-aeroelectric-list-server@matronics.com > [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of rampil > Sent: Wednesday, June 25, 2008 5:16 PM > To: aeroelectric-list@matronics.com > Subject: AeroElectric-List: Re: Need a to-220 connector > > > Another connector solution is to use quality connector machined crimp pins > on the three leads with mating gender crimp pins on the wiring. > Very thin heat shrink on the bare leads and exposed wires. Heat shrink over > the mated connections, then a wide piece over the regulator and the whole > set of connections. > > I agree with Bob regarding the stability (e.g. oscillations) of the 78/7900 > family without the input bypass cap and the output filter cap. > > Are you very sure that the Archer thingy will object to 24V? If you have > not done so, try calling them to find out. > > > I'm not an EE, I just played one through 4 years of grad school :-) > > -------- > Ira N224XS > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=189805#189805 > > >


    Message 10


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    Time: 07:50:17 PM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@cox.net>
    Subject: Need a to-220 connector
    At 09:34 AM 6/25/2008 -0400, you wrote: > >Thanks all for the comments, the one about the computer fans is an >especially good one... > >Ok, now I need a bit of an education... Bob, the Zener, will that step the >voltage down from 24v to 12v? > >That's all I really need is a reliable 12V out of 24v. The data sheet on >the LM7812C suggested that it didn't need any other components . . . If you look at the typical application schematics in the last pages of . . . http://www.aeroelectric.com/Mfgr_Data/Semiconductors/LM7812.pdf . . . you will see capacitors to ground on both the input and output leads of the device. These critters can go into oscillation at rather high frequencies when they resonate with ship's wiring. > but I'm >always open to better solutions and if the Zener will do it, then I'm all >for that. The zener inserts a constant 12V DROP in the supply voltage 24 becomes 12, 28 becomes 16, etc. The 7812 is a good choice. I'd SOLDER leads to input and output leads. Solder the smallest capacitors you can find directly to the leads of the device. Epoxy the caps to the regulator. Use same epoxy to beef up lead wires. Bolt the device right to structure for grounding. Bob . . .


    Message 11


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    Time: 07:50:20 PM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@cox.net>
    Subject: off line for a few days . . .
    Dr. Dee and I are off to visit my sister in Cincinnati over the weekend. Have a client to visit in Chicago on Monday. Will be back late Tuesday night. Bob . . . ----------------------------------------) ( . . . a long habit of not thinking ) ( a thing wrong, gives it a superficial ) ( appearance of being right . . . ) ( ) ( -Thomas Paine 1776- ) ----------------------------------------




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