# Need a circuit for a simple square wave generator with the least amount of onboard compone...

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Hi anybody got any idea where I can find the most simpliest square wave
generator with the smallest component counts?
I'll need something with pulse width control

also need a circuit for detecting current, and once it reaches a level of
current, it will trigger an output
again, most simpliest circuit there can be with least amount of components!

Thanks a million in advance!

Re: Need a circuit for a simple square wave generator with the least amount of onboard components, also need a current monitor..

Try an application based on the 555 timer for your square wave generator.
Simple and minimal components.

Cheers,
Alan

Re: Need a circuit for a simple square wave generator with the least amount of onboard components, also need a current monitor..

sorry I should've meant "duty cycle control" when I said "pulse width
control"

the frequency I need to generate is from 10kHz to 20kHz so I hope it's a
simple circuit, thanks again!

Re: Need a circuit for a simple square wave generator with the least amount of onboard components, also need a current monitor..

And the voltage output and current demand doesn't really matter as I can use
transformers and transistors/MOSFETs to drive the output, so basically I
just want the most simpliest generator, thank you!

Re: Need a circuit for a simple square wave generator with the least amount of onboard components, also need a current monitor..

"Bill T"

**  This  555 circuit will give variable duty cycle or PWM:

http://www.cpemma.co.uk/555pwm.html

For operation at 10 kHz,  change the pot ( VR1 )  to 10 kohms and C1 to 10
nF ( 0.01uF).

..........  Phil

Re: Need a circuit for a simple square wave generator with the least amount of onboard components, also need a current monitor..

will this be a square wave output or sine wave output?

Re: Need a circuit for a simple square wave generator with the least amount of onboard components, also need a current monitor..

"Bill T"

**  The output at pin 3 will be a very sharp rectangular wave  - even at 10
kHz.

555s are very versatile  -  but do not do sine waves without great
provocation  ;-)

...........  Phil

Re: Need a circuit for a simple square wave generator with the least amount of onboard components, also need a current monitor..

when you say sharp rectangular wave do you mean square wave or sawtooth
wave?

I think I sort of understand the circuit better now, and it seems the value
of C1 will affect the frequency, whereas the VR1 will affect the pulse
width, but it seems the value of VR1 will affect the frequency too, but how
do you work out the values to affect the output frequency? Do you just use a
variable capacitor to replace C1?

Re: Need a circuit for a simple square wave generator with the least amount of onboard components, also need a current monitor..

"Bill T"

** Stop being a PITA and build one.

It works like a charm.

............  Phil

Re: Need a circuit for a simple square wave generator with the least amount of onboard components, also need a current monitor..

ok, something clicked and I think I got it now, since you're using half of
VR1 to charge and the other half of VR1 to discharge, the whole VR1 value
determines the cycle. ie the waveform's frequency, so with a fixed value VR1
& C1 will yield a rough frequency value, but if I replace C1 with a variable
capacitor I will be able to fine tune the frequency value! Am I right?

so now where can I find a circuit for some "current monitor"? for eg. to
monitor the electric current passing through the motor M1? Would I use some
kind of op-amp or something?

Re: Need a circuit for a simple square wave generator with the least amount of onboard components, also need a current monitor..

It sounds like you are building a motor controller. Why not just buy
one? Or get plans for a "Motor controller", instead of getting plans for
each individual component of one?

Cheers,
Nicholas Sherlock

Re: Need a circuit for a simple square wave generator with the least amount of onboard components, also need a current monitor..

How much do they cost if I buy one? Where do I find them?

Re: Need a circuit for a simple square wave generator with the least amount of onboard components, also need a current monitor..

Hi I just went through that page, and the circuit is a pulse width control
thingy, with only 1 control - pulse width, do I need a separate circuit to
generate and control the waveform? ie. another 555 circuit and somehow
connect them together?

Re: Need a circuit for a simple square wave generator with the least amount of onboard components, also need a current monitor..

"Bill T"

**  Nope  -  that is the *whole* kaboodle.

Just one 555  - surprisingly simple, what  ?

........  Phil

Re: Need a circuit for a simple square wave generator with the least amount of onboard components, also need a current monitor..

It is surprising, and seems enough for what I need! Thanks!

Re: Need a circuit for a simple square wave generator with the least amount of onboard components, also need a current monitor..

A single chip microcontroller is the smallest component count solution
- 1 chip, no external components required except for your required
current sensor.
The PIC10F206 is a 6 pin SOT-23 package with internal 4MHz oscillator.
No PWM module, but you could probably do it in software.
The PIC12F683 is an 8 pin DIP/SO with 8MHz internal oscillator, 4
channel 10bit ADC, and a PWM module. The ADC could be used to detect
the current level.

Dave :)

Re: Need a circuit for a simple square wave generator with the least amount of onboard components, also need a current monitor..

For a wave generator Dick Smith had a kit  imported (under one of these
strange names) it was cheap and on a board about 40mm by 40mm based on
555. it does most wave form with a jumper.