23 Mar
2005
23 Mar
'05
9:54 a.m.
>>>> "vrs" == vrs <vrs at
msn.com> writes:
> I am currently modifying my Teletype ASR33 into a
LT33 according
> to the
vrs> DEC
> specifications to work with my PDP-8/L. Does
someone know what is
> a Thyractor (GE 6RS20SP4B4) ? Some kind of voltage clamping device
> ?. How could I make one, using, for instance a pair of thyristors
> or a pair
vrs> of
> zenner diodes ?
vrs> thyractor: "A marketing name by DAVIS, the thyractor was a
vrs> combination of a low loss choke (the reactor) and a thyristor."
vrs> I know NTE still markets a replacement for the 6RS20SP5B5 (but
vrs> not the 4B4). Unfortunately, I don't have the detailed specs
vrs> for the 4B4.
vrs> On the other hand, I think it is just a handy voltage clamp to
vrs> keep the semiconductor circuits from seeing the inductive spikes
vrs> from the TTY. Shouldn't be too hard to come up with something
vrs> else that would work.
If it's a voltage clamp, then either back to back zeners, or a MOV
should work. MOV might be the better choice since they are explicitly
designed as protective devices. Zeners would be ok in the larger
sizes, but the small ones may be fragile enough that they don't do
well in this application.
paul