RE: CCTV

["Keith Doxey" <ukha@xxxxxxx>]

500mA Quick Blow for each cable that you feed.
That way a fault only kills one circuit.

Fuseholder - Something inexpensive :-)
Rapid Electronics have suitable ones from
26p+vat t  40p+vat so M***** price of around £2-00 :-(

Keith

> -----Original Message-----
> From: Brian G. Reynolds [mailto:brian.g.reynolds@xxxxxxx]
> Sent: 30 July 2001 21:04
> To: ukha_d@xxxxxxx
> Subject: RE: [ukha_d] CCTV
>
>
> Keith, sorry t  bug you again but what rating fuse should I use?
>
> Also do you have a favourite panel mount fuse holder? I will look in
the
> Maplin catalogue and see if I can see anything that looks suitable.
>
> TIA,
>
> B.
>
>
> > Quick example.
> >
> > Although the original PSU is 12V @ 300mA, the camera is possibly
> > a 9V camera
> > drawing 300ma which will have a built in voltage regulator. The
Voltage
> > Regulator will be dropping 3V @ 300mA which is 0.9W or 900mW of
heat
> > disipated by the regulator. If you use a 15V power supply then
> > the regulator
> > will drop 6V @ 300mA  = 1.8W Whilst the actual regulator may be
> rated for
> > that power the heatsink may not be able to dissipate enough of
> > the heat and
> > the whole camera will run hotter than it should. Heat is the
> > biggest killer
> > of electronics.
> >
> >
> > A typical PC power supply can supply over 8A @ 12V. Thats enough
for at
> > least 24 cameras.
> >
> > Neatest way if you are rack mounting is t  fit panel mount
> fuseholders on
> > the front panel.
> > If you put an LED and resistor across the fuse it light if the
> fuse blows
> > indicating a fault, or you can put an LED on the outgoing side
> of the fuse
> > to show the supple is present.
> >
> >
> > FUSE BLOWN INDICATOR
> >  +ve --------fuse------------------device--0V
> >
> > 	   --LED--Resistor---
> >
> > or
> >
> > SUPPLY HEALTHY
> >   +ve --------fuse------------------device--- 0V
> >
> >                     --LED--resistor-------- 0V
> >
> >
>
>
>
>
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