how to generate 100 Hz clock signal ???

[inifinitrix]

how to generate a clock signal

i need a circuit to genarate 100 Hz clock signal.

what ic/device that i shoul use??

i'm want to find the cheaper way to build this circuit...

thanx

 

[Kral]

100hz clock signal

inifinitrix,
If your accuaracy and temperature stability requirements are not very stringent, you can connect a 555 timer IC as an astable multivibrator (oscillator). Otherwise, your best bet is to use a crystal osillator made from CMOS inverters, a capacitor, and a crystal, and divide the output using counter chips.
Regards,
Kral

 

[on1aag]

100 hz clock

Hi Inifinitrix,

This is the closest and cheapest Xtal/IC combination I could find,
you gonna have to add an extra flip-flop to get at 100 Hz.
If you replace the 3,2768 MHz Xtal by a 4,096 MHz type, you get
1 kHz at pin one.

on1aag.

 

[Euler's Identity]

100hz clock

It depends on how accurate you want.

If accuracy is not an issue, then go with the classic RC CMOS oscillator

Vo ----- CMOSinv1 ---- C --tap -- 10R ----- CMOSinv2 ----- Vo

tap ---- R ----- Vo

where:
t/2 = RC and f = 1/t

Actually, this will get you in the ballpark.

In reality, what you want is Vtap>CMOS threshold at 1/2t.

Vc = Vtap = Vin[1 - e^(-t/τ)] w/τ = RC

Use Vin = supply voltage. Note that this is the equation for Vc for this ckt,

Vsource (DC) ----- R ---- Vc ----- C ----- Gnd

not the actual circuit.

This gives

1 - Vtap/Vin = e^(-t/τ)

ln [1 - (Vtap/Vin)] = -t/τ

τ = -t/ln [1- (Vtap/Vin)]

Using f = 1/2t = 100Hz, 2t = 1/100, so t=1/200 = 5x10^-3s

τ = -5x10^-3/ln [1- (Vtap/Vin)]

Using Vsource = 5V and Vtap = 2.5V (actually between 1/3 and 2/3 of supply, but we just want ballpark...)

τ = -5x10^-3/ln [1- 2.5/5] = -5x10^-3/ln [0.5] = 7.213x10^-3s

Using C = 0.1uF,

R = τ/C = 7.213x10^-3/0.1x10^-6 = 72.1k -- use 75k

10R = 750k, but 1M is easier

Using these values and my simulator, I just got 61 Hz. Changing 75k to a 100k multiturn pot, f(min) = 45 Hz. 51k gets f = 89Hz. Using 39k just got me 116Hz. So the value you want is between 39k and 51k.

So, there ya go

But if you need higher accuracy, then go with the crystal oscillator given. However, crystal oscillators can be finicky, so I'd go with a bought oscillator module and follow it with a divider to 100Hz.

Added after 25 minutes:

Incidentally, for a device (with the above design I left), I'd go with a 74hc/hct 7404. However, if you want to turn the oscillator on and off, make it a NAND or NOR wired as an inverter, and then use one leg of inverter2 either as high or low switch.

If you don't like the 5V source, go wth the 4000 series CMOS, where the inverter is the 4069, which allows a 3-15v source. (That's great for a battery-powered gadget, as it continues running as a simple 9V battery drains.) Plus, you shouldn't have to change a thing, design-wise, as the ratio of Vtap/Vin will not be changing.

Betcha didn't know a square-wave oscillator was that simple, did ya? Yeah, I was amazed also. My days with the 555 oscillator are done for the most part. This thng rocks. I've used it many times at many different fo's.

However, I give you my usual disclaimer:

If you blow yourself up, or f isn't right, or you try to run it with food in a microwave oven, or you leave it to run in the burning hot sun in the Mohave desert, or you send it into the freezing cold of outer space, or you... you get the idea. You use it at your own risk. Yes, you can kill yourself with a nine volt battery! ...difficult, but you can. And I'm sure some guy who pours coffee down himself leaving a McDonalds drive-thru will do it too!

 

[neils_arm_strong]

what is oscillator 555 timer chip 100hz

use a 555 timer and appropriate R and C values.

 

[wvengineer]

how to generate 5 hz clock

What's the input signal?

 

[shaikhsarfraz]

how to generate clock signal

Hi,
If you want to generate 100Hz clock signal in my opinion the best option will be using a 555 timer with appropriate value of R and C.
Else you can also generate using 8085 and 8254.

Thanks
Shaikh Sarfraz

 

[alex_eng]

pic rc oscillator temperature stability

use a 555 timer and appropriate R and C values.
you can determine it`s value by 555 program

 

[Euler's Identity]

100hz 555

So many are calling for the 555, and I'd like to know why.

To me the CMOS RC oscillator is easier and uses less parts: two resistors, a capacitor, and an IC. Plus you get a few extra inverters that could be used later.

What's the advantage of the 555, aside from more output drive? The 555 will have to be made to be symetrical, for starters, as there are different charge and discharge paths, right? Plus you'll need another C to hold the Vctrl. Then there's that crazy equation which I never remember.

So what gives? What am I missing by recommendng the CMOS inverter over the 555?

 

[VSMVDD]

generate 29 mhz clock signal oscillator circuit

personaly i would stick to using either a pic c5xx series small 8 pin micro if you need adjustable clock
and for fixed
use a 1Khz Xtal and a /10 counter {cd4017}

 

[haytham]

astability hct khz

What's the input signal?

We have no inputs

inifinitrix kindly use 55 astable circuit. All you need is R,C and 555 chip.

Thanks
Haytham

 

[inifinitrix]

generating signal using 8085

thanx to all,i think i will use 555 chip

Added after 29 minutes:

ok,if i got this 100 hz signal,

what device that is suitable to divide this signal to be seconds,minutes,and hours???

i still blur to build this circuit... =(

somebody help me..