How to make a simple square wave generator (10 HZ to 100 HZ)

[tronoty]

555 timer square wave generator

Does anyone have a suggestion of how to make a very simple Square Wave generator that can be regulated from 10 HZ to 100 HZ (And may be up to 300 HZ).

Input Voltage is 12 Volts DC
Output can be anything between 5 Volts to 12 Volt
Duty Cycle is not so important, so 50% would be perfect

Thank you

Tronoty

 

[IanP]

555 square wave generator

The 555 timer is a very good candidate for this job ..
Use it in astable configuration, instead of fixed resistors install a potentiometer .. and off you go ..
Here:
**broken link removed**
you will find detailed description of this IC ..

Regards,
IanP

 

[tronoty]

square wave generator using 555 timer

Thank you IanP for the info and the great link.

Do you know if the 555 Timer allows to keep the ON-Time the same for the frequency range?

In other words, I would like to keep the output ON-TIME at lets say 2 milli seconds from low to high frequency, so the duty cycle is constantly changing.

Possible with the 555?

Thanks

Tronoty

 

[IanP]

square wave generator using 555

With the 555 you can do the opposite: the OFF time can be constant ..

Ton=0.693 * (R1+R2) * C
Toff=0.693 * R2 * C

If you vary R1 and keep R2 constant Toff will remain constant, too ..

So, if you use simple transistor inverter or NOT gate you can invert the square wave and have the ON time constant ..

Regards,
IanP

 

[tronoty]

simple square wave generator

Thank you so much, this was very helpful information.

Tronoty

 

[coolguy_ar]

how to create a square wave

Hi,
With regard to making a square wave gen using a 555 timer at 50% duty cycle, one way is to bypass the R2 using diodes during the charging and discharging times suitably!

Can a constant current source also be used in this case instead of R1(a current mirror circuit) which would help to produce such a wave?

 

[k7elp60]

how to make a wave generator

Another way to make a 50% duty cycle with the 555 is connect a 1k resistor from pin 3 to Vcc. Tie pins 2 & 6 together. Put the timing resistor from pin 3 to the junction of pins 2 & 6, put the timing capacitor from pins 2 & 6 to ground. The time now becomes: T=1.386RC.

 

[coolguy_ar]

555 timer square wave

To k7elp60:
Which means the normal resistors are not to be used in the 555 cicuit b/w pins 7 and 6 or 8! So basically, the charge is thru the resistor connected b/w pin 3 and 6, while discharge is thru the original resistor??

 

[k7elp60]

square wave generator schematic

To k7elp60:
Which means the normal resistors are not to be used in the 555 cicuit b/w pins 7 and 6 or 8! So basically, the charge is thru the resistor connected b/w pin 3 and 6, while discharge is thru the original resistor??

Charge and discharge is thru the resistor connected between pins 3 and 6.

 

[coolguy_ar]

square wave generator

Could I get a schematic of yours please?? I just need to confirm a few things

 

[k7elp60]

how to make a simple generator

Schematic of 555 timer 50% duty cycle square wave

 

[mrcube_ns]

555 square wave

Hi,

You can try with this circuit.

Here you have 50% of duty cycle!

Best regards.

Mr.Cube

 

[funnynypd]

how to make a square wave

Either 555 or PIC12F with internal clock will work.

 

[coolguy_ar]

how to create square wave

To Mr.Cube

Using the op-amp with unipolar supply does cause a hell lot of problems especially with the virtual ground. Plus, in your circuit, the capacitance is between the inverting input and "actual ground". Its requires that it be with the virtual gnd.

It is much better to use the op-amp using bipolar!

The following schematic is the actual one using a bipolar supply. You can probably add the resistors at the non-inverting input!

 

[coolguy_ar]

555 square wave oscillator

The output from the op-amp if used with the bipolar supply, will be positive and negative.

How do I convert this wave b/w +V and -V into a wave which is b/w +V and gnd?

It is not full-wave rectification that I want to do. And I just don't want clamping either!!

I want to "TRANSLATE" the same info contained at the original signal to the new one. Any ideas???

 

[BryanL]

30 hz square wave 555 timer

Shouldn't frequency be F=1/1.386RC as opposed to F=1.386RC

Schematic of 555 timer 50% duty cycle square wave

 

[Sadegh.j]

squarewave generator using 555 timer

Use an A-stable

 

[mandrei]

50 hz square wave generator

Shouldn't frequency be F=1/1.386RC as opposed to F=1.386RC

Schematic of 555 timer 50% duty cycle square wave

You have right, the photo has wrong notation!!

1/1.386RC is actualy the frequency

1.386RC is the period

 

[tronoty]

square wave generator 555

Thank you all. this was very helpful.

I have used the 555 Timer and it worked very well.
I have used the output of the 555 to drive a small transistor and this way I get a perfect inverted signal to drive my system.

Thanks again

Tronoty

 

[garg29]

12 volt square wave

Tronoty , what values of R&C you choose