26 Apr
2012
26 Apr
'12
1:33 p.m.
Eh...tony, have you read the datasheet of Signetics 25120 WOM memories?
:o)
---
Enviado do meu Motorola PT550
Meu site: http://www.tabalabs.com.br
----- Original Message -----
From: "Tony Duell" <ard at p850ug1.demon.co.uk>
To: <cctalk at classiccmp.org>
Sent: Thursday, April 26, 2012 3:32 PM
Subject: Re: Disadvantages of solid state media (was Re: Advantages...)
Chuck Guzis wrote:
Why does Vff have to be AC? Surely it's the rms vlaue that really
matters, so 6.3V DC would be OK too [1]. And IIRC the unregulated output
of the mains adapter was on the expanison connector of the Speccy, so
you could use that with a dropping resistor.
[1] Vff = 6.3V nearly always implies an indrectly-heated cathode, so the
polarity and whether it's AC or DC make very little difference.
-tony If that was the case, why didn't they go with
state of the art in 1972
and use the Signetics 25120 memory chip? --Chuck
Probably due to the inconvenience of needing 6.3Vac for the Vff supply.