Eric,
The microamp current draw is not an issue. The fragility of such devices to
voltage spikes is an issue so I want to keep things primitive and simple. This
device will be connected to the main buss which is connected to the windlass.
Perhaps heavy filtering will protect the device.
The control switch(es) must be positive. No push-push. One pushbutton for on,
and a different one for off, or alternatively a momentary center off toggle
switch, my usual choice.
An indicator near the load is no good as the load is usually out of sight.
I need to able to a switch on a dark and stormy night an feel assured that the
device is either on or off, as I need it.
Norm
S/V Bandersnatch
Lying Julington Creek
30 07.695N 081 38.484W
----- Original Message -----
From: Eric T.
To: [email protected]
Sent: 7/29/2008 7:24:25 PM
Subject: Re: [Liveaboard] Latching relay control
Norm,
The 74C73 MAXIMUM current use ( at highest rated frequency) is 100 microamps.
The FETs would only see power long enough to latch the relay.
100 microamps run continuosly would take 16.66 DAYS to consume 1 amp-hour.Your
batteries self discharge a lot faster than that.
So, you want to be able to move the switch in different directions, or do you
want an indication when the load is turned on?
LEDs make a low power indicator, are very reliable, and can be mounted near
the load so you don't need another wire.
A 74C73 IC is 30 or more year old technology, will do what you want, and can be
bought online anywhere. If you put a 1 microfarad capacitor between pins 7
(ground) and 14 (Vcc, +12 volts) , and a 100 ohm resistor between pin 14 and
+12 volts it will last forever. Well, longer than you will anyway.
Am I missing something? Do you want me to build you one so you can try it?
That will take a while as I am now totally dependant on other people for things
like stripping wire, soldering, etc. This one hand stuff sucks, big time.
Eric Thompson
S/V Procrastinator
South San Francisco
[EMAIL PROTECTED]
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