Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!samsung!think!mintaka!oliveb!tymix!strider!stimac
From: stimac@strider.uucp (Michael Stimac)
Newsgroups: sci.electronics
Subject: Re: ESR of copper oxide rectifiers
Message-ID: <3103@tymix.UUCP>
Date: 12 Dec 89 22:57:11 GMT
References: <1989Dec12.022128.3128@tapa.uucp>
Sender: news@tymix.UUCP
Reply-To: stimac@tymnet.com (Michael Stimac)
Organization: Tymnet NTD, San Jose CA
Lines: 26

In article <1989Dec12.022128.3128@tapa.uucp> larry@tapa.uucp (Larry Pajakowski) writes:
>In refurbishing my old Lionel train transformer I replaced a copper oxide
>rectifier of about 1in. diameter with a silicon diode.  In the original
>circuit a compensation winding of 5 volts was switched in series with the
>copper oxide diode to keep the output from sagging too much.  I'm trying

(typically, this rectifier is part of the circuit to blow the whistle
on older Lionel trains, which were activated via a DC-sensitive
relay)

Are you getting unsatisfactory results changing only the diode,
without the extra resistor? (ie, does the train speed up when you
sound the whistle?) Since the transformers were not well-regulated,
the output would drop when the whistle motor kicked in (nearly
doubling the load); I think the extra five volts is to compensate
for this poor regulation more than for the resistance of the
copper oxide diode. 

>to get some idea of the series resistance of the copper oxide diode so I
>can put a resistor in series with the silicon diode.  I suspect the
>resistance is about 1 - 2 ohms.
>
>Larry Pajakowski

Michael Stimac (TCA 72-4800)
....sun!oliveb!tymix!stimac