555 to CD4013: Direct Connection?

[The New Guy]

Hello All,

Attached is a schematic for a frequency divider circuit, that I want to build. I found it on the internet. I see that there is no resistor between 555 Pin 3 (Out), and CD4013 Pin 3 (Clock). Can this be done?

Thanks

 

[bertus]

Hello,

When the NE555 and CD4013 are on the same powersupply, that should be fine.

Bertus

 

[Harald Kapp]

I agree with Bertus. What makes you think there should be a resistor?

 

[Audioguru]

Why is the CD4013 not connected to the power supply?
Why is the +5V missing a decoupling capacitor?
Why are you using an old 555 instead of a new Cmos 555 in the Cmos CD4013 counter circuit?

 

[Harald Kapp]

Why is the CD4013 not connected to the power supply?

It definitely needs to be connected to +5 V and GND. However, this may simply be a typical omission you will find in many schematics. If only one supply voltage is present, it s often assumed that all ICs are connected to that voltage. Doesn't make it easier for amateurs, though

Why is the +5V missing a decoupling capacitor?

Possibly because this is a not too well designed hobby circuit? Who knows. I totally agree, better yet, each chip (IC1, IC2) should have its own decoupling capacitor, right next to the supply pins, connections to the IC as short as possible.

Why are you using an old 555 instead of a new Cmos 555

Where do you take this information from? The schematic says only "IC1 555).
Of course, it is highly recommendable to use the modern CMOS variant.

 

[Audioguru]

The thread starter's first post here was about a "555". Maybe he does not know about its antique problems and does not know about a Cmos 555.
Intersil shows than an old 555 has a 400mA (!) shoot-through current each time it switches and the datasheet for an old 555 says that its decoupling capacitors are mandatory to protect associated circuitry. The Cmos 555 has no huge shoot through current.