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4P2T switch -what's available

E

Eeyore

Jan 1, 1970
0
I need a 4 pole double throw switch, but all I can find are toggle
switches like this:
http://www.maplin.co.uk/Module.aspx?TabID=1&ModuleNo=2343&doy=10m2

What other types of switches of this type (4P2T) are available, and
where?
I'd prefer something like a PCB solderable slide-switch in a vertical
position, but I'll consider anything smart and modern looking.

4 pole switches aren't very common. What load current and voltage are you
switching ?

Graham
 
4 pole switches aren't very common. What load current and voltage are you
switching ?

It's just for video signals. I don't know the voltage/currents, but
I'm pretty sure it can't be more than 12V and a few mA. Any low
voltage switch should do.
 
L

Lostgallifreyan

Jan 1, 1970
0
It's just for video signals. I don't know the voltage/currents, but
I'm pretty sure it can't be more than 12V and a few mA. Any low
voltage switch should do.

Maybe a pair of DG111 analog switches?
http://www.maxim-ic.com/quick_view2.cfm/qv_pk/1315

I'm not sure how well they cope with video signal rates, but if you use
individual switches to form SPDT pairs, two IC's will be enough, and you
can control it with any SPDT toggle switch you like. You can get your
alternating control levels directly from a physical toggle switch.
 
E

Eeyore

Jan 1, 1970
0
It's just for video signals. I don't know the voltage/currents, but
I'm pretty sure it can't be more than 12V and a few mA. Any low
voltage switch should do.

Does it have to be a physical switch 4 pole ? How about a single pole switch of
your choice and some relays ?

Do you mean actual video or RF btw ?

Graham
 
E

Eeyore

Jan 1, 1970
0
Lostgallifreyan said:
Meant DG211...

The channel resistance may be a bit high actually or I'd have suggested that
too. You could use discrete fets though.

Graham
 
The channel resistance may be a bit high actually or I'd have suggested that
too. You could use discrete fets though.

All of this sounds very good except I wouldn't know where to start :-(

My electronics knowledge restricts itself mainly to creating working
circuits out of schematics and other practical things. Not designing
stuff from scratch.

The circuit I'm working on in Eagle for creating a complete PCB is the
following diagram I found somewhere:
http://img236.imageshack.us/img236/2712/stmsyncvganl4.gif

It allows for a standard PC (VGA) monitor to be connected to an Atari
ST as opposed to just the special Atari monitor itself.

If the VGA monitor is a multisync type (e.g. it can handle all of the
Atari ST frequencies (*)) the switch can be used to choose colour or
mono modes.

(*)
Atari ST monochrome mode:
35.70 KHz horizontal
71.2 Hz vertical

Atari ST colour mode:
15.75 KHz horizontal
50/60 Hz vertical
 
L

Lostgallifreyan

Jan 1, 1970
0
All of this sounds very good except I wouldn't know where to start :-(

My electronics knowledge restricts itself mainly to creating working
circuits out of schematics and other practical things. Not designing
stuff from scratch.

The circuit I'm working on in Eagle for creating a complete PCB is the
following diagram I found somewhere:
http://img236.imageshack.us/img236/2712/stmsyncvganl4.gif

It allows for a standard PC (VGA) monitor to be connected to an Atari
ST as opposed to just the special Atari monitor itself.

If the VGA monitor is a multisync type (e.g. it can handle all of the
Atari ST frequencies (*)) the switch can be used to choose colour or
mono modes.

(*)
Atari ST monochrome mode:
35.70 KHz horizontal
71.2 Hz vertical

Atari ST colour mode:
15.75 KHz horizontal
50/60 Hz vertical

Have a look at the DG211. Looks like you might be ok with two of those.
Eeyore mentioned that the on resistance might be a bit high, but as you're
using a circuit that uses 62 ohm resistors in three of the four lines, it
won't matter there. The 'monochrome sensor' line is probably a DC level
state line, so it won't matter there either.

If you can handle soldering and veroboard, you'll not have much trouble.
Just check VERY carefully before connecting to the computer's 5V supply.
The Analog switch IC's are very easy to use. The most awkward bit will just
be working out how you will route the connections.
 
L

Lostgallifreyan

Jan 1, 1970
0
Just realised, you might need a 12V supply. That Atari plug appears to
provide one, which is helpful. The DG211 can work with 22V in some
versions, 12V should be safe for all.
 
A

Andre Majorel

Jan 1, 1970
0
It allows for a standard PC (VGA) monitor to be connected to an Atari
ST as opposed to just the special Atari monitor itself.

If the VGA monitor is a multisync type (e.g. it can handle all of the
Atari ST frequencies (*)) the switch can be used to choose colour or
mono modes.

(*)
Atari ST monochrome mode:
35.70 KHz horizontal
71.2 Hz vertical

Atari ST colour mode:
15.75 KHz horizontal
50/60 Hz vertical

Your VGA monitor can go down to 16 kHz horizontal sync ? Which
model is it ? I've never seen any that went below about 30 kHz.
 
Your VGA monitor can go down to 16 kHz horizontal sync ? Which
model is it ? I've never seen any that went below about 30 kHz.

Not a VGA monitor.
I was referring to Multisync monitors. I used to have an NEC Multisync
II which could handle all of the Atari ST's sync rates.
 
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