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question on viewing VSS and Vgnd pins on 4017DB 5-stage Johnson counter in Multisim 8 tia sal

Greetings,

I'm trying to connect a 555 timer circuit to a 4017DB 5-stage Johnson counter in Multisim 8 how does one get the Vss and Vgnd pins to show up on the 4017DB

5-stage Johnson counter so I can connect them to the 555 timer? Example of the circuit
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The pins are different why?

is thier a group dedicated to multisim or electronic work bench I should/could post to?

Thanks

Reply to
<sal
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counter in Multisim 8 how does one get the Vss and Vgnd pins to show up on the 4017DB 5-stage Johnson counter so I can connect them to the 555 timer?

should/could post to?

Vss is ground, it's just the designation used for with MOS transistors. Vdd is the power supply as Vcc is for TTL devices. It doesn't matter that you show your 555 ground connected to Vss so long as Multisim knows it's ground.

Using real components, one wouldn't jump the ground of one chip to the ground of the other. Rather you would connect your power source and ground to the plug board power rails and simply jump the chip power pins to the appropriate rail.

There are situations where grounds are isolated but this is not one.

Reply to
Lord Garth

Looking at SCHEMATIC DIAGRAM, the 555 does NOT appear to be wired for

"Use of a 555 timer circuit to produce "clock" pulses (astable multivibrator)"

Take a look at:

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for some information on the 555.

Dave

Reply to
Dave

Why is that? Jumping the ICs' ground-pins or making a separate coupling from each GND-pin to the GND-rail they will still be electrically common, won't they?

--
Rikard Bosnjakovic                         http://bos.hack.org/cv/

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Reply to
Rikard Bosnjakovic

It's convenient to connect the power to a near-by bus. Wide power traces are better than narrow traces impedance wise and the wide trace also provides an easy place to solder on a decoupling capacitor very close to the IC. Further, many schematics presume you know the chip needs power so they may not be shown.

Reply to
Lord Garth

The power and ground are clearly shown on the pictorial, albeit they've omitted any bypass caps. The OP was asking how to connect them in his simulator program. For that, I'd say check the program's docs.

"sal" had written: "I'm trying to connect a 555 timer circuit to a 4017DB 5-stage Johnson counter in Multisim 8 how does one get the Vss and Vgnd pins to show up on the 4017DB 5-stage Johnson counter so I can connect them to the 555 timer? Example of the circuit

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The pins are different why?"

I'm guessing that sal is saying that the 555 connection looks different from the ones in the data books. It's not a problem - it just makes very narrow pulses - the discharge resistor is zero plus parasitics.

Cheers! Rich

Reply to
Rich Grise

the

board

coupling

common,

traces

I presuming that Multisim doesn't show the power and ground inputs since that's a given. I could be wrong, I don't own a copy so I'm WAGing!

Reply to
Lord Garth

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