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how to harden the outputs - relays — Parallax Forums

how to harden the outputs - relays

ArchiverArchiver Posts: 46,084
edited 2003-10-31 14:33 in General Discussion
--- In basicstamps@yahoogroups.com, "widgetbot" <widgetbot@y...>
wrote:
> I would like to make hardened outputs on the basic stamp.
> I know that it could be done with an optical relay.
> but how? what type and where to buy?
> I'm looking at controling a 120vac at about 10 amps.
> Thanx.


that type of power is often done with a mechaincal relay.
depending on your checkbook, you can buy SSR, these solid state
relays take 5V and can switch 10 amps easily. but may go into the
$20.00 range per unit.

A electromagnetic relay will often be cheaper, but mechanical things
often have shorter lives.

when looking at a relay, considder that the coil is isolated from the
switching contacts so your pins are protected.

Thge contacts have 3 ratings. AC, DC and AC inductive for motors.
the inductive loads are always lower ratings as the spike from the
state change will arc the contacts when opening the contacts.

What type of load are you switching ?

www.mpja has a 5V PN# 12525-RL $5.95 15A@120VAC
a 12VDC coil, 12272-RL $1.95 10A@120VAC
Mechanical relays may require a darlington to fire. an 8 channel
UNL2803 has an internal diode to kill the inductive spike from the
coil.

a single channel TIP122 has much more power, and also has the
interanl diode.

the solid state route is already protected and usually does not need
additional circuits.

SSR's are ALWAYS AC unless specifically noted otherswise.

an SSR is $4.95 14689-RL will run direct from a stamp pin, fully
isolated. 10A @ 120 VAC (AC only)
or 14352-RL 25A @ 24 to 230 VAC (AC only) $6.95

more than you wanted to know right ?

Dave

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2003-10-31 14:33
    a crydom D1210 will switch 120vac at 10 amps and a crydom D2410 will switch
    240vac at 10 amps. Any relay probably should be isolated from the stamp
    with a transistor switch.
    jim http://www.geocities.com/jimforkin2003/


    Original Message
    From: Dave Mucha [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=PAfUdj1I0UHH3M5k24UlDjJrHBr6LIOw-N-vUAT9gXBl53cPfAh_TREkJA1MYaREIGQT9TNrBuT6DSda]davemucha@j...[/url
    Sent: Thursday, October 30, 2003 9:36 PM
    To: basicstamps@yahoogroups.com
    Subject: [noparse][[/noparse]basicstamps] Re: how to harden the outputs - relays


    --- In basicstamps@yahoogroups.com, "widgetbot" <widgetbot@y...>
    wrote:
    > I would like to make hardened outputs on the basic stamp.
    > I know that it could be done with an optical relay.
    > but how? what type and where to buy?
    > I'm looking at controling a 120vac at about 10 amps.
    > Thanx.


    that type of power is often done with a mechaincal relay.
    depending on your checkbook, you can buy SSR, these solid state
    relays take 5V and can switch 10 amps easily. but may go into the
    $20.00 range per unit.

    A electromagnetic relay will often be cheaper, but mechanical things
    often have shorter lives.

    when looking at a relay, considder that the coil is isolated from the
    switching contacts so your pins are protected.

    Thge contacts have 3 ratings. AC, DC and AC inductive for motors.
    the inductive loads are always lower ratings as the spike from the
    state change will arc the contacts when opening the contacts.

    What type of load are you switching ?

    www.mpja has a 5V PN# 12525-RL $5.95 15A@120VAC
    a 12VDC coil, 12272-RL $1.95 10A@120VAC
    Mechanical relays may require a darlington to fire. an 8 channel
    UNL2803 has an internal diode to kill the inductive spike from the
    coil.

    a single channel TIP122 has much more power, and also has the
    interanl diode.

    the solid state route is already protected and usually does not need
    additional circuits.

    SSR's are ALWAYS AC unless specifically noted otherswise.

    an SSR is $4.95 14689-RL will run direct from a stamp pin, fully
    isolated. 10A @ 120 VAC (AC only)
    or 14352-RL 25A @ 24 to 230 VAC (AC only) $6.95

    more than you wanted to know right ?

    Dave






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