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Path: utzoo!utgpu!utcsri!greg
From: greg@utcsri.UUCP
Newsgroups: sci.electronics
Subject: Re: I need a telephone ring detector chip
Message-ID: <4683@utcsri.UUCP>
Date: Mon, 27-Apr-87 17:59:35 EDT
Article-I.D.: utcsri.4683
Posted: Mon Apr 27 17:59:35 1987
Date-Received: Tue, 28-Apr-87 00:59:16 EDT
References: <228@phoenix.PRINCETON.EDU> <7940@utzoo.UUCP> <441@haddock.UUCP> <565@inuxh.UUCP>
Reply-To: greg@utcsri.UUCP (Gregory Smith)
Organization: CSRI, University of Toronto
Lines: 15
Summary: 

In article <565@inuxh.UUCP> rmrin@inuxh.UUCP (D Rickert) writes:
>Ten megs will not cause any problems.  I would suggest builiding a circuit
>such as this in a metal box to guard against component overheating in the
>event funny voltages get on the phone lines.

In order to dissipate 1/4 W in a 10M resistor, you have to apply 1,581 V
across it. And the 10M resistor will dissipate 98% of the power in the circuit.

The capacitor will fry long before the resistors get warm.


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Greg Smith     University of Toronto      UUCP: ..utzoo!utcsri!greg
Have vAX, will hack...