25-07-2012, 03:05 PM
4017 details
4017 details.docx (Size: 520.6 KB / Downloads: 24)
Pin connections
The 4017 available from Rapid Online decade counter has ten outputs which go HIGH in sequence when a source of pulses is connected to the CLOCK input and when suitable logic levels are applied to the RESET and ENABLE inputs.
Basic operation.
4017 is designed to drive higher current loads, so it is OK to connect LEDs with series resistors directly to its outputs
You should assemble the prototype board version of the circuit in stages, checking that each stage is working properly before proceeding the to the next stage.
To see the 4017 in action, you need to build an astable. The easiest way to do this is using a 4093 Schmitt trigger NAND gate integrated circuit. Start by building the astable section on your prototype board
It is good practice with CMOS circuits to insert a decoupling capacitor, 47 µF or 100 µF, across the power supply. (This helps to prevent the transfer of spikes along the power supply rails.)
Next add the 4017. The pulse output from the astable is connected to the CLOCK input. For normal operation, the RESET and ENABLE inputs must be connected to 0 V
Beasties need power supplies! Don't forget to connect pin 16 of the 4017 to +9 V and pin 8 to 0 V.
Connect a single LED with a 680 W series resistor to output 0 of the 4017.
Count the pulses. The output 0 LED should flash once for every 10 flashes of the LED connected to the astable.
Continue, adding new resistor/LED stages for outputs 1 and 2. Don't disconnect the power supply. It helps to see that the new connections make the LEDs illuminate in the correct sequence
Connect a second prototype board and keep on adding new LEDs until all 10 outputs are used
RESET and ENABLE inputs
Modify your circuit so that the RESET and ENABLE inputs are each connected to 0 V through a 10 kW pull down resistor. Initially, the behaviour of the circuit will be unchanged. Add 'flying leads' as indicated below: