Fred, I have used thermistors numerous times, the most recent being installation in the primary winding of a filament transformer on my Drake L4B linear. I've noticed no adverse effects in this application having measure the filament voltage in standby and operate/transmit. Some critical instances might have a slight drop in regulation due to the added primary circuit resistance but I'd imagine that it would be minimal in most cases. As a side note, proceed with caution when buying a "step start" circuit, box, etc. One product I know of (I own two) claims the device is a surge protector and step-start for 220 v that I use on my linears. Yes, it does provide a "slow" turn on BUT in the best of cases, for 1/4 to 1/2 of an AC cycle. Trust me, the caps haven't charged and the filaments haven't warmed in that short period of time. Manufacturer rep agreed with me but said "...it does afford some degree of inrush protection." The key word is what is meant by degree, hi hi. 73, Evan -----Original Message----- From: [email protected] To: [email protected] Sent: Thu, Jan 27, 2011 1:09 pm Subject: Re: [Drakelist] Drakelist Digest, Thanks to all on the light bulb issue. Thanks to everyone for their replies on the light bulb issue. I will look further into the thermistor application. I was concerned about the statement about the power supply regulation when using a thermistor. Any additional comments about that issue. I don't want to create any additional problems by trying to solve this one. Thanks 73 de Fred WD8ADG _______________________________________________ Drakelist mailing list [email protected] http://mailman.zerobeat.net/mailman/listinfo/drakelist
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