It is a clock, with 12hour clue, little simpler in the manufacture from the SamClock. It’s a designing that became George Kordogiannis in 1990, which was modified and corrected in enough points by my, until it reach in the current form. Most completed that uses is TTL, apart from the IC9 until IC13, that is CMOS, that they have the faculty to drive display Common Cathode.
In the place of 4511, can be placed the 74LS47, which can drive display Common Anode. In this case it will be supposed they are changed display Common Cathode in the Fig.2, with Common Anode, changing of course and connection in DIS1 until DIS5 display. In the SL10, come in the pulses frequ. 1HZ , which then are divided successively by the IC2 until IC4 and the round this gates, ensuring the clue of time, in Hours, Minutes and Seconds. The Q1 drive display the tens of hours, but only the B and C Led of DIS6 display, ensuring clue 1, when needs the clue of hours it’s 10, 11, 12. The voltages that supply the circuit are divided in two lines. The voltage +5VA supplies all IC except the IC9 until IC13 and is supplied with voltage in case of break of network voltage, on the contrary the voltage of +5VB, supplies only the IC9 until IC13 and display and is interrupted in case of interruption of network voltage, ensuring thus economy in battery. If the Q1 is hot, can be placed on a small heatsink.
Main Clock Part List R1=2.2Kohm 1/4W 5% IC5-7=74HC32  Q1=BD139 on Heatsink
R2……R38=470ohm 1/4W 5% IC6=74HC08  SL1….SL5=7 pin connector
IC1-4=74HC390  IC8=74HC04  SL6-7=2 pin connector
IC2-3=74HC92  IC9….IC13=4511  or [74LS47]  SL8=3 pin connector
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