Subject: From: Date:

Re: [ECS] micro-redac and relays David Mccoll Fri, 1 Jan 1999 18:36:22 -0800

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Mark S,
The transition should be spontaneous with no delay at all. You have a good
point about the residuals in the power-pak. There must be a capacitor inside
the power-pak. You can bleed the stored energy off with a resistor connected
across the two leads before the digital input of Redac. I suggest placing
the resistor before the fuse and resistor for the input.

Start with a 2.2kOhm  and move down until you get it working well. Check how
hot the resistor gets with the receiver on. When the receiver is on, the
added resistor will dissipate the energy and get hot. This is ok but if it
gets too hot it can be a hazard. If the resistors are 1/2 Watt then they can
dissipate 1/2 Watt max. A 1/8 Watt resistors will be a little small for the
job. You can halve the heat through the resistor by using 2 resistors in
parallel but you MUST double the value of both resistors when you parallel
them. This shares the load between them. When you are finished you may want
to spring a couple dollars for a 5 Watt ceramic resistor.

I figure a good value would be 500Ohm across 12Volt = .024Amp and .28Watt.
A 1 Watt will do, and a 5 Watt is more than adequate.  If you want to use
other values you can use the Ohm's Law calculator at this url:

http://webhome.idirect.com/~jadams/electronics/ohms_calc.htm

DAvid M

-----Original Message-----
From: Mark Sekelsky <Mark@sekelsky.com>
To: ecs-list@netbloc.com <ecs-list@netbloc.com>
Date: Thursday, December 31, 1998 4:16 PM
Subject: RE: [ECS] micro-redac and relays


>David,
>
>Thanks for the resistor lesson.  The 2.2 didn't work but the 1K sort of
>does.  With only a fuse in place there is about a 3-4" delay before the
item
>state changes to HIGH.  I assume this is residual power in the transformer.
>With the 1K resistor in place that delay is 8-9" but it does change to HIGH
>100% of the time.  I can certainly live with this but wonder if it means I
>should be trying yet another resistor or not.
>
>Happy New Year!
>
>Mark S
>
>-----Original Message-----
>From: David Mccoll [mailto:dmccoll@intergate.bc.ca]
>Sent: Wednesday, December 30, 1998 4:13 PM
>To: ecs-list@netbloc.com
>Subject: Re: [ECS] micro-redac and relays
>
>
>Mark S
>Your connections sound correct. Get it to work 100% before you add the fuse
>and resistor. If the 10K resistor gives you trouble move down to a 4700
that
>is a Yellow, Violet, Red, Gold. If that does not work then move down to a
>2.2K or 2200 which would be Red, Red, Red, Gold. If that does not work then
>go to a 1K or 1000 which is Brown, Black, Red, Gold.
>
>Originally you said the power pak was 5V DC 150mA. What are you using now ?
>
>Here is some gunk on resistors. This is very simple stuff but on the
surface
>it may look complicated. The Gold band is what is referred to as the
>"tolerance" of the resistor and is usually the last band.
>
>Gold is 5% -- most common tolerance
>Silver is 10% -- not too common
>
>The first 3 bands are the value.  Here is the way I learned to calculate
it.
>Bad  ---  Black -- 0  -- .0
>Boys  --- Brown -- 1 -- 0
>Rape --- Red -- 2 -- 00
>Our  --- Orange -- 3 -- 000
>Young --- Yellow -- 4 -- 0000
>Girls --- Green -- 5 -- 00000
>But  --- Blue -- 6 -- 000000
>Violet ---- Violet -- 7 --0000000
>Goes --- Gray -- 8 -- 00000000
>Without  -- White -- 9 -- 000000000
>
>The first 2 bands are the value and the third band is the multiplier which
>is the number of 0's to add after the value. So 4.7 K.Ohms = 4700 Ohms =
>Yellow, Violet, Red and Gold for the 5% tolerance. The 10KOhm resistor
would
>be Brown, Black and Orange the multiplier is usually assumed to be 5% Gold.
>A 100 Ohm resistor is Brown Black Brown and a 10 Ohm is Brown,Black, Black
>
>Keep up the good work.
>
>DAvid M
>
>
>
>

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