27 Nov
2013
27 Nov
'13
9:37 p.m.
Hello,
ANyone know if mouser carries anything that'll work for this? I'm going to
try and make home-made cab kits for a DEUNA and DQQNA. I seem to have
found the connectors (to plug in to the berg and the AUI socket)
The things I need to grab next are: wire/cable and those fuses. As I need
to get caps and a thermistor from Mouser, i'd prefer 'em all from the same
place.
--
Cory Smelosky
http://gewt.net Personal stuff
http://gimme-sympathy.org Projects
27 Nov
27 Nov
9:53 p.m.
On Nov 27, 2013, at 16:37, Cory Smelosky <b4 at gewt.net> wrote:
Hello,
ANyone know if mouser carries anything that'll work for this? I'm going to
try and make home-made cab kits for a DEUNA and DQQNA. I seem to have
found the connectors (to plug in to the berg and the AUI socket)
The things I need to grab next are: wire/cable and those fuses. As I need
to get caps and a thermistor from Mouser, i'd prefer 'em all from the same
place.
Sure. Get a fuse holder and attach leads to it (this is what the
real cab kit does anyway). You don't want to be in the business
of resoldering wires when the fuse blows. You should be able
to mount the holder in the bracket with a metal punch or
appropriate drill bit as well, much like the real cab kit.
- Dave
28 Nov
28 Nov
7:35 p.m.
Sure. Get a fuse holder and attach leads to it (this
is what the
real cab kit does anyway). You don't want to be in the business
One of the Cabkits used a circuit breaker, not a fuse.
You used to be able to get in-line fuseholders, I am not sure if you
still can. They were commonly used in cars. A plastic tube with a
bayonet-fitting end cap and a couple of contacts and a compression spring
inside. You fed a wire through each end (and through the spring and
soldered said wires to the cotnacts. Then put a 1+1/4" fuse (3AG IIRC)
inside and fitted the bits toegether.
As I said, commonly used in cars, so should be fine for the 12V supply to
an ethernet transceiver. IIRC the PERQ 3A has one in the +12V feed to the
hard disk for some odd reason.
-tony
27 Nov
27 Nov
10:26 p.m.
Showing my dumbness: how critical are voltage ratings on fuses?
Since the fuse has close to no voltage drop across it, it seems as if
the voltage is really none of its business until it blows, and even then
it just needs to have enough dielectric strength to be sure it really
won't conduct, and I would think any glass tube would be OK up to many
hundreds of volts ... Unless what we're really talking about is the film
of former fuse filament (the F.F.F.F.) that flashed onto the inside of
the tube when the fuse blew. Which seems very fancy.
In any case am I wrong in thinking a fuse can be used at *far* lower
than its rated voltage w/o ill effects? 25V seems like an oddball rating
which would be dumb to pay extra for when a 125V or 250V fuse would work.
John Wilson
D Bit
28 Nov
28 Nov
12:10 a.m.
On Nov 27, 2013, at 17:26, John Wilson <wilson at dbit.com> wrote:
Showing my dumbness: how critical are voltage ratings on fuses?
Since the fuse has close to no voltage drop across it, it seems as if
the voltage is really none of its business until it blows, and even then
it just needs to have enough dielectric strength to be sure it really
won't conduct, and I would think any glass tube would be OK up to many
hundreds of volts ... Unless what we're really talking about is the film
of former fuse filament (the F.F.F.F.) that flashed onto the inside of
the tube when the fuse blew. Which seems very fancy.
A fuse voltage rating generally refers to its rated dielectric strength.
Thus a 120v fuse will stave off at least 120v when it's blown.
I've never heard of a 25v fuse, but a 120v fuse should be fine;
what makes the fuse blow is the I^2*R dissipated power.
- Dave
1:20 a.m.
On 11/27/2013 04:10 PM, David Riley wrote:
A fuse voltage rating generally refers to its rated
dielectric strength.
Thus a 120v fuse will stave off at least 120v when it's blown.
I've never heard of a 25v fuse, but a 120v fuse should be fine;
what makes the fuse blow is the I^2*R dissipated power.
Aren't most automotive fuses specified for 32V? But you'll never find
one for 1.5A--automotive fuses tend to be for multiple amps. Most
common fractional-amp fuses are specified at 250V.
--Chuck
1:53 a.m.
On Nov 27, 2013, at 20:20, Chuck Guzis <cclist at sydex.com> wrote:
Aren't most automotive fuses specified for 32V? But you'll never find one for
1.5A--automotive fuses tend to be for multiple amps. Most common fractional-amp fuses
are specified at 250V.
Yeah, you want to be able to block the nominal working voltage
plus any inductive kicks you might get from the load when the
fuse blows. I usually see 250v fuses for consumer stuff, 120v was
just an example. Automotive fuses are usually 7.5 amps and up,
in my experience, though I've seen 3.25 in the wild (there's one in
my lighter-port inverter).
- Dave
2:18 p.m.
The voltage rating has some importance other than
being able to open. The voltage drop at the rated
current can also be an issue. A 250 volt fuse in a circuit
that runs at 120 volts can easily tolerate 1/2 volt
drop while a low voltage circuit may not have the same
ability.
In order for a fuse to blow, it has to get hot. To get
hot it has to consume power. That is I*E.
Dwight
From: fraveydank at gmail.com
Subject: Re: 1.5A 25V fuse w/ leads
Date: Wed, 27 Nov 2013 20:53:54 -0500
To: cctalk at classiccmp.org
On Nov 27, 2013, at 20:20, Chuck Guzis <cclist at sydex.com> wrote:
Aren't most automotive fuses specified for 32V? But you'll never find one for
1.5A--automotive fuses tend to be for multiple amps. Most common fractional-amp fuses
are specified at 250V.
Yeah, you want to be able to block the nominal working voltage
plus any inductive kicks you might get from the load when the
fuse blows. I usually see 250v fuses for consumer stuff, 120v was
just an example. Automotive fuses are usually 7.5 amps and up,
in my experience, though I've seen 3.25 in the wild (there's one in
my lighter-port inverter).
- Dave
4:55 p.m.
On 11/28/2013 06:18 AM, dwight elvey wrote:
The voltage rating has some importance other than
being able to open. The voltage drop at the rated
current can also be an issue. A 250 volt fuse in a circuit
that runs at 120 volts can easily tolerate 1/2 volt
drop while a low voltage circuit may not have the same
ability.
In order for a fuse to blow, it has to get hot. To get
hot it has to consume power. That is I*E.
For very low voltages, I could imagine where this is an issue, but in
all cases, it's not I*E, but I*2*R that matters more.
--Chuck
7:40 p.m.
Showing my dumbness: how critical are voltage ratings on fuses?
Not very. You can always use a fuse with a higher voltage rating than
specified.
Since the fuse has close to no voltage drop across it,
it seems as if
the voltage is really none of its business until it blows, and even then
it just needs to have enough dielectric strength to be sure it really
won't conduct, and I would think any glass tube would be OK up to many
hundreds of volts ... Unless what we're really talking about is the film
of former fuse filament (the F.F.F.F.) that flashed onto the inside of
the tube when the fuse blew. Which seems very fancy.
Baically yes. There's also the point that an arc may form betwene the
ends of the fuse whire when it blows, and you don't want that arc to
carry on arcing. The olvate rating is the maximum votlage it will
certainly safely break.
Other than special types, such as those 2-blade fuses used in modern-ish
cars, almost all fuses I see over hrre are good to 250V. They can be used
on mains, on 120V circuits, on lower votlage stuff, etc. It is _very_
uncommon to spedify the votlage rating when buyign a fuse, unless it's
some soem special purpose, such as a partucualrly high voltage unit.
In any case am I wrong in thinking a fuse can be used at *far* lower
than its rated voltage w/o ill effects? 25V seems like an oddball rating
Sure.
which would be dumb to pay extra for when a 125V or
250V fuse would work.
I wonder if 25V is a tpyo or truncation for 250V, which is a very common
voltage rating for fuses.
-tony
7:30 p.m.
Hello,
ANyone know if mouser carries anything that'll work for this? I'm going to
try and make home-made cab kits for a DEUNA and DQQNA. I seem to have
found the connectors (to plug in to the berg and the AUI socket)
The things I need to grab next are: wire/cable and those fuses. As I need
to get caps and a thermistor from Mouser, i'd prefer 'em all from the same
place.
Iseem to remerbthe DEUNA cabkit has a little bit of circuitry in it -- an
inrush limiter or soemthing. It's shown in the printset, and would not be
hard to copy, but it's not jsut cables and connectors.
-tony
4052
days inactive
4053
days old
10 comments
6 participants
participants (6)
-
ard＠p850ug1.demon.co.uk -
b4＠gewt.net -
cclist＠sydex.com -
dkelvey＠hotmail.com -
fraveydank＠gmail.com -
wilson＠dbit.com