Phone minute beep decoder circuit with NE555, CD4017

Published:2011/8/30 2:09:00 Author:Jessie | Keyword: Phone minute beep, decoder | From:SeekIC

At present, our country telephone is executed with method of using minute as timing charging unit, except the charging in the first 1 min. Namely, the first time is fixed charging. Whenever enter the next time, the first 1s will immediately add the one-time charging. For the longer time's call speaking, the over 1 min should be paid low proportion in the whole conversation. But to those calls which often finished in the 1 min, even talk time delays 1 s, the over fee's proportion is high in the whole fee. The timing remind decoder circuit is shown as the chart. Full circuit is composed of the 6s time-base generator, 6s separate-frequency timing display and minute timing display.



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