[Coco] [coco] coco CNC

[Gene Heskett]

On Sunday 17 February 2008, Kevin Diggs wrote:
>Gene Heskett wrote:
>> I don't think the cassette relay's contacts are up to a: switching line
>> voltage, and b: the amp or so the dremel draws.  That means a booster
>> relay, or a triac.  There are probably 500+ circuits to use a triac
>> available on the net, and the cassette relays contacts would last 3 days
>> past the rapture. The triac could even be driven from a flip-flop that
>> would be another address on your 1 of 16 decoder as there are triacs with
>> only 50 microamps of gate current required available from several src's.
>
>Gene,
>
>	What are the odds the power transistor in the PS will make it even to
>the rapture?
>
Barring some surge, probably about 1000x better than the electrolytic filter 
caps in it.  Particularly if its a switcher rather than an analog design.  
Switchers stress the caps considerably harder due to the required very low ESR 
to make the switcher a successful design.  When that goes up, so does the 
cap, often explosively.

Some caps CAN last better than others, I have a pair of 270k u-f's in the 
brute force analog ps that drives the motors on my mill, running those 25 
volt rated caps at 28 volts.  They are good, and about 45 years old as they 
came out of one of the first 2" quadruplex broadcast videotape machines ever 
built.  But that is the exception to the rule that otherwise proves it. 
Generally, for analog stuff, 10-15 years, for switchers, half that.

-- 
Cheers, Gene
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