Extended counter using CD4017
This diagram can be used to get a 24 output counter, with three 4017 IC.
At the start condition all pin 15 are connected to the ground, so R0 is energized. A 555 multivibrator sends the clock signal to IC1, which activates the outputs from R0 to R8.
Once the tenth output of IC1 takes the high level, RS1 turns on (it keeps that condition until the end of the cycle).
So IC2 starts taking the clock signal, and it activates the outputs from R9 to R16.
RS2 turns the clock signal to IC3, which activates the outputs from R17 to R23.
Once RS3 is energized, all pin 15 take the high level, so the circuit takes the start condition.
Relay on-off with singol button
This simple circuit can be utilized to drive a monostable relay through a single button switch. At the start condition the relay does not work. When I press the button (P) T1 is energized through R1 and R2, and the capacitor charges. The coil is jumped by
the button. So, once I release it, the relay turns on.
T1 keeps the high level through 10-6 relay switch.
When I press the button again T2 is energized (the exchange switch is now closed between 9 and 5).
The current which flows through T2 collector lets T1 switch off.
When I release the button T2 takes the low level.
T1 would switch on 0.01 seconds after.
But the coil turns off within 0.003 seconds only. Than the circuit takes the start condition.
Relay coil: 12 Volts, 140ohm
R3, R4: 3watt
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Extended counter using CD4017 |
