Connect with us

Faulty temperature sensor

Discussion in 'Electronic Basics' started by Jurgen Bauer, Dec 25, 2004.

Scroll to continue with content
  1. Jurgen Bauer

    Jurgen Bauer Guest

    Hello,

    I would like to check out a temperature sensor for my central heating
    cylinder. 2 cables coming from the sensor.

    What voltage do I need?
    What should change with the rising temperature?

    Thanks.
     
  2. Jamie

    Jamie Guest

    i don't know but do you mean 2 wires or 2 cables?
    there is a difference.
    cables have 2 or more wires and even conductors
    like drain wire.
    wire on the other hand is a single conductor with
    some kind of insulation around it.
    in any case.
    it's hare to say what type you have ?., could be a
    Type-J, in many cases i have seen 2 sets of these types
    wrapped around heating tubes.
    only 1 needs to be used, in any case they are very small conductors
    and mostly the J type which is 2 unlike metals twisted and electrically
    bonded together.
    the idea is when its heating one wire will contract more than the
    other causing tension forces which produce a small amount of current to
    the ratio of heat.
    with these types you need a HI-Z micro volt meter to see the voltage
    coming out of it.
    some 10Meg-Z DMM's have a low scale that will read it.
    under an ohm meter it will appear to be shorted.
    --
    now the RTD types ( Resistor thermo device).
    that is basically a resistor that decreases in value
    as the temp goes up. these was have 2 wires
    ---
    then you have the IR (infra Red), where light is used to generate an
    effect with a IR detector since temp produces IR in most cases that i
    know of..
    those comes in a different variety.. , modular types which require a
    gnd, Vcc and 2 optional outputs.
    some times it just a simple IR diode with a lens which only have 2
    wires.
    so take your pick..
    P.S.
    the Twisted Wire types normally use the same type of
    material as the lead wire to the controller.
     
  3. Thanks for the detailed explanation. I'm working with a Micrel MIC280 and it
    use a 2N3906 transistor junction as its remote sensor. Micrel has a demo
    board and software that runs off a PC's printer port and you can set "high"
    and "low" level trip points.

    I'm working on a USB temp controller with multi-zone sensor inputs based
    around the MIC280. Its been a fun project.
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-