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Freezer Alarm

Im want to build this circuit.

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I am a novice at this.

The diagram states that the alarm will go off when the freezer gets to be 0 C.

Actually I think this is too late. Any freezer that goes kaput will hold th e temp for perhaps 24 hours before it gets to 0c. By that time the food is now pretty much defrosted. And must really be used up.

How can this circuit be changed to say go off at maybe -3 C. or there about s.

Thanks all.

P.S.

I cant seem to get any listed parts locally. I want to buy them from SAYAL electronics because they are near me and I can pick them up. But I cant see m to find any of the parts on their web site. I have tried to do comparison s but they dont seem to have any of those parts either. (and maybe IM doing something wrong) I'M sure they have what I need but I just dont have the s kill to compare parts, if any Canuck (or other kind person could mach parts that would be great)

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I dont like buy things across the border or on line.

Reply to
steve
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temp for perhaps 24 hours before it gets to 0c. By that time the food is now pretty much defrosted. And must really be used up.

electronics because they are near me and I can pick them up. But I cant seem to find any of the parts on their web site. I have tried to do comparisons but they dont seem to have any of those parts either. (and maybe IM doing something wrong) I'M sure they have what I need but I just dont have the skill to compare parts, if any Canuck (or other kind person could mach parts that would be great)

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  • 5 Volt | ++-------+ + | + | .-. | | |
Reply to
Jamie

be 0 C.

d the temp for perhaps 24 hours before it gets to 0c. By that time the food is now pretty much defrosted. And must really be used up.

bouts.

YAL electronics because they are near me and I can pick them up. But I cant seem to find any of the parts on their web site. I have tried to do compar isons but they dont seem to have any of those parts either. (and maybe IM d oing something wrong) I'M sure they have what I need but I just dont have t he skill to compare parts, if any Canuck (or other kind person could mach p arts that would be great)

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K R with this

  To (-)  input.

That will work but you'll have to futz around to set the pot to the right place. So the original schematic might have been easier for you to understand if he used a 361 kohm resistor in the upper arm and the same 499 kohm resistor in the bottom. Then you just need to look up that thermistor, find it's resistance at -3 C and plug that resistance into the place where the 361 kohm is now... Does that make any sense?

George H.

Reply to
George Herold

temp for perhaps 24 hours before it gets to 0c. By that time the food is now pretty much defrosted. And must really be used up.

normal freezer temp is -20C. I've not datalogged what the actual temp swing is in a typical freezer though. The defrost cycle would probably mess with that depending on where you measure the temp.

Reply to
Cydrome Leader

C.

temp for perhaps 24 hours before it gets to 0c. By that time the food is now pretty much defrosted. And must really be used up.

Good deep freezers don't auto-defrost. Only refrigerator-freezer combos do that. ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| Phoenix, Arizona  85048    Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

C.

temp for perhaps 24 hours before it gets to 0c. By that time the food is now pretty much defrosted. And must really be used up.

abouts.

True, but large restaurant type upright freezers can have defrost cycles.

There's a gigantic Traulsen freezer at work with a really rediculous 3 digit LED and 4 button "intelligent" controller. It's easy enough to set a temperature, but what the scrolling cryptic messages mean is beyond even the service people.

They all say f*ck it and just do normal troubleshooting like on any normal refrigeration device.

F- on the usability and intuitiveness of an "intela-traul" controller.

Reply to
Cydrome Leader

C.

the temp for perhaps 24 hours before it gets to 0c. By that time the food is now pretty much defrosted. And must really be used up.

abouts.

Yep. In the kitchen we have a separate SubZero Freezer and SubZero Refrigerator... big mama's ;-) ...Jim Thompson

--
| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    | 
| Phoenix, Arizona  85048    Skype: Contacts Only  |             | 
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  | 
| E-mail Icon at http://www.analog-innovations.com |    1962     | 
              
I love to cook with wine.     Sometimes I even put it in the food.
Reply to
Jim Thompson

0 C.

the temp for perhaps 24 hours before it gets to 0c. By that time the food i s now pretty much defrosted. And must really be used up.

uts.

L electronics because they are near me and I can pick them up. But I cant s eem to find any of the parts on their web site. I have tried to do comparis ons but they dont seem to have any of those parts either. (and maybe IM doi ng something wrong) I'M sure they have what I need but I just dont have the skill to compare parts, if any Canuck (or other kind person could mach par ts that would be great)

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Thanks for the suggestions. I'm going to see if I get the parts then will probably get back to the grou p with questions. On the defrost thing. Most Deep freezes don't have defrosters I don't think . Those that do only heat the coils behind the plastic wall compartment to remove frost and ice from the coils. This "should" not cool the food, if it did then there would be a problem. This means that the sensor on these typ e of freezers should be in a small box or something in the freezer, not tap ed or stuck to the plastic wall of the freezer, as the wall of the freezer can get a little warm with the defrost cycle. Although there is probably pl aces in the compartment that don't have cooling coils. Thanks. I'm sure I will be back again.

Reply to
steve

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