555 RC voltage rating

[The New Guy]

Hello everyone,

I am new, and I am trying to get started with a simple astable 555 circuit. I am trying to generate seven different frequencies (square wave pulse, 20% duty cycle): 73 Hz, 146 Hz, 292 Hz, 584 Hz, 1168 Hz, 2336 Hz, 4672 Hz. I am keeping R1 at a constant 1k Ohms.
The R2 and C values are:
(73 Hz) R2: 9,383.6 Ohms, C: 1.0 uF
(146 Hz) R2: 10,014.41 Ohms, C: .47 uF
(292 Hz) R2: 10,731.33 Ohms, C: .22 uF
(584 Hz) R2: 5,677.23 Ohms, C: 0.1 uF
(1168 Hz) R2: 12,643.05 Ohms, C: 0.047 uF
(2336 Hz) R2: 13,539.162 Ohms, C: 0.022 uF
(4672 Hz) R2: 14,943.08 Ohms, C: 0.01 uF

When I run these values through any of the online 555 calculator websites, they seem to give me what I am looking for. I read that I will have to use diode between R1 and R2 to go below a 50% duty cycle:

My question is: what brand, voltage rating, type of capacitors should I use for this project?

The same question for the diode and the resistors. Should I use a multi-turn trimmer potentiometer?

I was thinking of building this circuit run on a regulated 5 volt supply. My goal is to then feed the Output (pin 3) into an LC circuit and create sinewaves at these frequencies. My only goal after that is to step up the voltage through a transformer for more power.

If any of this seems tenable to you all, could you please help me with buying components, as I am so new to this.

Thank you for your time.

 

[Alec_t]

Welcome to EP!
Sorry to burst your bubble, but I think you'll be disappointed if you try to use a 555 to generate those frequencies. You seem to be expecting a tolerance better than 1%, but what tolerance is actually acceptable?
If you check the datasheet for the 555 you will see that both the THRES and the TRIG voltage levels vary widely from one part to another, their maximum and minimum values being 10% or more removed from the 'typical' values. Online calculators are based on the 'typical' values so give only a rough guide to actual component values needed. You will also see that pulse timings are dependent on temperature.
A microprocessor would be a better bet for accurate frequency generation.

 

[Chemelec]

Why 7 Frequencies?
And a Transformer will NOT Increase POWER.
It Just Steps up Voltage but at a Reduced Current.

 

[Audioguru]

Sure a transformer steps up the power. If the output of the 555 is 10V peak and the load is 1k then the power is 0.1W peak. The output of the 555 is 10mA peak.

If the transformer steps up the voltage to 31.6V peak then the power in the 1k ohms load is 1W and the current in the 555 output is 111mA when its output max voltage drops to 9V peak.

 

[Chemelec]

Sure a transformer steps up the power. If the output of the 555 is 10V peak and the load is 1k then the power is 0.1W peak. The output of the 555 is 10mA peak.

If the transformer steps up the voltage to 31.6V peak then the power in the 1k ohms load is 1W and the current in the 555 output is 111mA when its output max voltage drops to 9V peak.

What makes you believe his load is 1K?
He doesn't say.

 

[duke37]

Seven octaves?
The frequencies seem to be a factor of two between each.
Generate 4672Hz with your 555 and then put into a digital divider to get the other frequencies.There were dividers for organ frequency generation to do this.

 

[Audioguru]

A CD4060 counter IC has an oscillator and 14 stages to give up to 14 octaves of squarewaves outputs.

 

[The New Guy]

Seven octaves?
The frequencies seem to be a factor of two between each.
Generate 4672Hz with your 555 and then put into a digital divider to get the other frequencies.There were dividers for organ frequency generation to do this.

Thank you! that was a huge help. I suppose I should have mentioned that this is for an LED flasher circuit.
Any particular IC you would recommend?

 

[The New Guy]

Welcome to EP!
Sorry to burst your bubble, but I think you'll be disappointed if you try to use a 555 to generate those frequencies. You seem to be expecting a tolerance better than 1%, but what tolerance is actually acceptable?
If you check the datasheet for the 555 you will see that both the THRES and the TRIG voltage levels vary widely from one part to another, their maximum and minimum values being 10% or more removed from the 'typical' values. Online calculators are based on the 'typical' values so give only a rough guide to actual component values needed. You will also see that pulse timings are dependent on temperature.
A microprocessor would be a better bet for accurate frequency generation.

Thankyou! I appreciate what you are saying. Just know that this is the first time I am building a 555 circuit. It is all a learning curve for me.

 

[Audioguru]

I suppose I should have mentioned that this is for an LED flasher circuit.

You have selected audio frequencies. LEDs flickering at these frequencies will look the same as LEDs that are continuously powered by DC. You cannot see a frequency that is 24Hz or higher which is why a movie flickers at 24 frames per second. The lights in your home flicker at 120Hz. Do you notice it?