Hello I am in the process of building a 555 timer circuit. I was wondering if i am able to remove the potentiometer and replace it with some type of resistor. I would like my led to produce around an 60-80hz signal.
This is the drawing I am using.

Any suggestion would be greatly appreciated.

 

Yes, you can.

Unfortunately, the pot in that schematic will only adjust the ON vs OFF time.

R1 is really a bit too small; it should be more in the range of 2.7k to 3.3k.

Do you want the ON vs OFF time to be over 53%, or exactly 50%, or somewhere between 3% and 97%?

 

Anywhere from 50-60% is fine. So I can remove "P1". Replace R1 with around 3k resistor. But what should I do with "D1" and "D2"?

 

Change R1 to 27k and attach it to the junction of 6,2, and C1. The diodes aren't necessary because they were used to steer the different duty cycles.

 

Change R1 to 27k and attach it to the junction of 6,2, and C1. The diodes aren't necessary because they were used to steer the different duty cycles.

Gee, this is the first really bad advice I've seen you give.

It just won't work like that.

Take another shot at it.

There needs to be resistance between Vcc and pin 7 (R1), and there also needs to be resistance between pin 7 and the junction of C1/pin 2/pin 6 (R2).

You can use a diode from C1 to pin 7 to match R1/R2 pretty well to get a 50/50 duty cycle.

 

Oh #$*^&. I was looking at the monostable drawing.

 

Just for background, the circuit that the op posted is a pwm circuit to dim LEDs, and works well for that. The only limitations are that the duty cycle is roughly between 5-95%, meaning the LEDs can not be turned all the way off or to full brightness.

 

OK, the attached schematic should provide a 70Hz output frequency with a fixed 50% duty cycle.

If you want the duty cycle to be variable but keep the 70Hz flash rate, that can be done, too.
(eta) Oops - snipped off the ground symbol from the bottom. Trust me, it WAS there before I ham-fingered the editing.

[eta]
Andrew,
If you're thinking of using this circuit in your truck - please don't do that. It's not suitable for automotive use.

 

Couple of articles I've written that might help.

LEDs, 555s, Flashers, and Light Chasers

The 555 Projects

My Cookbook

 

Thanks all for the advise