Discussion in 'General Electronics Discussion' started by 010101, Jan 4, 2011.

1. ### 010101

4
0
Jan 4, 2011
Hi I'm a bit confused about the attached circuit diagram.

Is only resistor R1 connected to pin 3 of the CMOS and R2 connected to pin 2 and so on? OR are resistors R1 to R4 collectively connected and pins 2, 3, 4, 7 connected together?

The link to the circuit is http://www.zen22142.zen.co.uk/Circuits/Timing/sqt.htm.

Thanks!

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2. ### (*steve*)¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥdModerator

25,480
2,828
Jan 21, 2010
The curvy line thingy connecting to pins 2, 3, 4, and 7 indicates a bus. That is, a series of parallel conductors that are grouped together for some reason. They are not connected together.

At various points it shows what those bus wires are connected to. Each one has 3 connections, a 2K7 resistor, and the anode of 2 diodes. Each place where the bus is shown as going has the pin number and the function in parenthesis.

Similarly, "Clock" is shown at several points, these are connected together.

There is a connection shown for pin 16 to supply power to the 4017, and all the ground symbols are connected together and then connected to the -ve side of the battery or power supply (this is not shown -- you are assumed to know)

I hope this helps, and sorry if I have covered stuff you already know.

3. ### KMoffett

723
75
Jan 21, 2009
The numbers refer to the counter bits of the 4017... the numbers in red inside the IC symbol. "0" (pin 3) connects to R1, D1, and D5. "1" (pin 2) connects to R2, D2, and D6. And so on...! It's like a parallel 4 wire buss. I think it was just to make the schematic simple to draw.

Ken

4. ### 010101

4
0
Jan 4, 2011
Thanks! I get it now

Regarding the connection for pin 16, am I suppose to get it from between C3 and C4 (there's an arrow with 16 written next to it)

And...where does clock go to???

5. ### 010101

4
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Jan 4, 2011

Thanks Ken.
As I place the components on a breadboard, I can see that this simplified schematic actually has many connections.

6. ### KMoffett

723
75
Jan 21, 2009
Yes the junction of C3 and C4 go to pin 16 on the IC. There are also two connections to pin 14 from R13 and from C5

Ken

7. ### 010101

4
0
Jan 4, 2011
Thank you KMOffett and (*Steve*)!