adams@swbatl.sbc.com (Tom Adams - 235-7459) (09/12/90)
In article <1437@gold.GVG.TEK.COM> grege@gold.GVG.TEK.COM (Greg Ebert) writes: >About a week ago, somebody inquired if it's OK to leave the gate of a >TRIAC open to turn it off. > >I popped open an older "solid-state" relay, which is actually a reed-relay >with the contacts in series with the gate lead of a TRIAC. So, the answer I'm confused here. A reed relay? What provides the magnetic field that operates these guys? -- uunet!swbatl!adams or adams@swbatl.sbc.com Tom Adams: 314-235-7459: Southwestern Bell Telephone Advanced Technology Lab BOOKS WANTED: pre-1930 radio, electrical & scientific topics
grege@gold.GVG.TEK.COM (Greg Ebert) (09/12/90)
## I(Greg Ebert) write:
##
## I popped open an older "solid-state" relay, which is actually a reed-relay
## with the contacts in series with the gate lead of a TRIAC.
adams@swbatl.UUCP (Tom Adams - 235-7459) writes:
#
# I'm confused here. A reed relay? What provides the magnetic field that
# operates these guys?
The coil is driven by a TTL-level signal, and includes a clamp diode. This
provides isolation from the AC line. One contact goes to the gate, the other
through a resistor to the anode. When the contacts close, gate current is
provided (for *both* half-cycles).
My only gripe about the relay is that it doesn't have an internal snubber
to limit dv/dt. A di/dt inductor would be handy, too. Geez, what can you
expect from Radio Snack ?
An opto-TRIAC/LED would be more elegant...