[MRCA] Mystery Project

[Mike Feher]

Seems a lot of you feel that Breck is a JHS student. He probably even then knew all the things mentioned here. I sure did. It worked for him, so, he calculated everything correctly. It was a clever approach for his needs. 73 – Mike 

 

Mike B. Feher, N4FS

89 Arnold Blvd.

Howell NJ 07731

908-902-3831

 

From: mrca-bounces at mailman.qth.net <mrca-bounces at mailman.qth.net> On Behalf Of scottjohnson1 at cox.net
Sent: Tuesday, September 16, 2025 3:30 PM
To: ac2eu at yahoo.com; 'B. Smith' <smithab11 at comcast.net>; 'Christopher Bowne' <aj1g at sbcglobal.net>
Cc: mrca at mailman.qth.net
Subject: Re: [MRCA] Mystery Project

 

 

 

 

Keep in mind that a tungsten filament lamp has 10-12 times the resistance at normal operating temp as it does at room temperature, so can be used as a ballast/ current limiting some applications, but makes a poor dropping resistor.  If it is AC, consider using face to face Zeners rated at the voltage drop needed, if the drop is small, series forward biased diodes can be used similarly.  Make sure the current and power dissipation ratings are not exceeded.

Scott W7SVJ

 

From: mrca-bounces at mailman.qth.net <mailto:mrca-bounces at mailman.qth.net>  <mrca-bounces at mailman.qth.net <mailto:mrca-bounces at mailman.qth.net> > On Behalf Of ac2eu--- via MRCA
Sent: Tuesday, September 16, 2025 8:43 AM
To: B. Smith <smithab11 at comcast.net <mailto:smithab11 at comcast.net> >; Christopher Bowne <aj1g at sbcglobal.net <mailto:aj1g at sbcglobal.net> >
Cc: mrca at mailman.qth.net <mailto:mrca at mailman.qth.net> 
Subject: Re: [MRCA] Mystery Project

 

Subbing the filaments with bulbs is a tricky proposition. They have to have the same current rating as the tube or the string voltage will be out of balance. 

Ever see that old trick electricity question about to bulbs in series? One is a 40 watt and the other is a 100 watt. which will be brighter?

 



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