On 2007-04-24, John Fields wrote:

begin 644 HILOSTAT.pdf
M)5!$1BTQ+C0*)0HS(#`@;V)J"CP\"B]0F]D=6-EB`H4$1&+5A#:&%N9V4@
M,RXV,"XP,3`Y(%PH5VEN9&]WR!84%PI*0HO0W)E871I;VY$871E("A$.C(P
M,#P-#(T,38R,C,X+3`V)S`P)RD*/CX*96YD;V)J"C4@,"!O8FH*/#P*+T9I

I see two comparators and a voltage divider, and positive feedback
that introduces schmitt action and shifts the trigger levels depending
on how the switch is set. and a small transistor driving (presumably)
a small relay.

with the switch down it activates the relay when the voltage is below
the lower limit, with it up it triggers when the upper limit is exceeded

well, if the 393 can its output down below 0.6V it does, otherwise
it's a ccircuit for turning relays on.

Bye.
Jasen

On 27 Apr 2007 23:42:25 GMT, jasen wrote:

On 2007-04-24, John Fields wrote:

begin 644 HILOSTAT.pdf
M)5!$1BTQ+C0*)0HS(#`@;V)J"CP\"B]0F]D=6-EB`H4$1&+5A#:&%N9V4@
M,RXV,"XP,3`Y(%PH5VEN9&]WR!84%PI*0HO0W)E871I;VY$871E("A$.C(P
M,#P-#(T,38R,C,X+3`V)S`P)RD*/CX*96YD;V)J"C4@,"!O8FH*/#P*+T9I

I see two comparators and a voltage divider, and positive feedback
that introduces schmitt action and shifts the trigger levels depending
on how the switch is set. and a small transistor driving (presumably)
a small relay.

with the switch down it activates the relay when the voltage is below
the lower limit, with it up it triggers when the upper limit is exceeded

well, if the 393 can its output down below 0.6V it does, otherwise
it's a ccircuit for turning relays on.

---
It could get iffy...

Fix = change R8 to 3k.

Thanks,


--
JF