How to create square wave without generator?

Thread Starter

enesene

Joined Mar 3, 2020
12
I need squarewave to run this circuit (2-4-6-8 up counter) but i don't have generator. Is there any way to create square wave from DC battery? Or is it necessary to use square wave?

abc.png
 

Alec_t

Joined Sep 17, 2013
11,141
With the post #2 'differentiator' circuit, V1 gets driven both above and below the supply rails, so care must be taken to ensure R2 has a high enough value to limit the input current to the first gate to a safe level. The circuit also has two stable states which it can get stuck in.
Here's an alternative 'integrator' circuit which avoids those situations :-
Osc2.png
 

dl324

Joined Mar 30, 2015
10,519
From a TI CD4093 datasheet:
1584372140699.png
If you don't want a control input, you can tie the two inputs together or use a single inverter from a CD40106. You may need to buffer the output in some cases.
 

DarthVolta

Joined Jan 27, 2015
395
From a TI CD4093 datasheet:
View attachment 201627
If you don't want a control input, you can tie the two inputs together or use a single inverter from a CD40106. You may need to buffer the output in some cases.
So if using the RC circuit time constant, and just duty cycle calculations, these types of circuits can be solved, since the well working op-amp's take care of the details.

So you don't have to do any crazy transistor models.


I've been avoiding playing with digital chips, like making osc., but I'll remember that , thanks dl324
 

dl324

Joined Mar 30, 2015
10,519
So you don't have to do any crazy transistor models
A CMOS Schmitt inverter only takes 6 MOSFETs. I haven't tried making one from discrete MOSFETs, but have used the MOSFETs in a CD4007 to make one. May try making one with discrete devices now that I have some complementary MOSFETs.
 
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