[Heathkit] OFF TOPIC. I THINK

[B Riches]

The 5ar4 cathode is indirectly heated - meaning it takes 15-30 seconds =
to start working - the 5as4 filament is the cathode - heating up in a =
few seconds.  5ar4 is a good idea as the other tubes in the piece of =
equipment have warmed up and will be ready to draw current when the =
rectifier warms up.  The prevents the high voltage from attempting to =
rise to a much higher value as it would with a directly heated rectifier =
or solid state diode - therefore stressing the filter condencers until =
the other tubes have warmed up sufficently to draw current.

Regards,

Bill Riches, WA2DVU
Cape May, NJ
  ----- Original Message -----=20
  From: Murray Grandy=20
  To: heathkit list=20
  Sent: Sunday, February 29, 2004 12:51 AM
  Subject: [Heathkit] OFF TOPIC. I THINK


  IS THERE ANYONE HERE WHO CAN EXPLAIN THE FOLLOWING. 5AR4/GZ34 =
RECTIFIER
  TUBE, AND 5AS4 DIFFERENCE. BOTH HAVE THE SAME CONNECTIONS. THE 5AR4 =
HAS A
  SEPARATE CATHODE, ALTHOUGH IT IS CONNECTED TO THE FILAMENT PIN #8. THE =
5AS4
  DOES NOT HAVE THE CATHODE AS SUCH. ARE THESE TUBES INTERCHANGEABLE. IF =
NOT,
  WHY NOT. DOES IT REALLY MAKE THAT MUCH DIFFERENCE.
  MURRAY (VE7MGY)


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