Saturday, January 24, 2009


Automatic time indicator for the Telephone

As, you already know, the telephone calls are charged on the basis of the time duration for which the call has been made. If the call is continued after the standard time is over, then your calling time will be extended and the charges will be added up accordingly. It is very difficult to keep an eye on the time elapsed while you are busy in talking on the phone. This novel circuit does just this for you while you are talking on the phone. The circuit gives out a warning signal after 2.5 minutes of starting the call.
The On/Off touch plates are made from the conducting silver paper strips and fixed in a suitable position on the cabinet.

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