50hz clock ** Update **

[tom314]

I would like to create a 50hz ttl clock, but I am unsure of the best way to do it. I was thinking of using a 555 timer, but it can be difficult to get a 50% duty cyle using the 555 timers. I was then thinking about a crystal oscillator, but it looks like they are for much higher frequencies. Are there any other options, or do I just have to make due with the 555 timer?

** Update **
Ok, I finished building my design and it is currently running off of a 9v battery. Is it possible to use a dc power supply that plugs into the wall that supplies 9v, and 1.5A instead? I am worried that the current will be way to much for my circuit. I know for a fact that my voltage regulator only handles up to an amp. So I guess my question is will the supply output1.5 amps to my circuit, or will my circuit just draw the neccesary amount of current to run.

 

[TuxDave]

Differential Pair + Big Capacitor + Resistors = Oscillator! Yay!

 

[Geniere]

Try the HTC555.

 

[Mark R]

Crystal oscillator and binary divider

Use a 3.27680 MHz crystal and a 16 bit divider.

That crystal frequency looks odd, but is a standard value - it was specifically chosen for 50 Hz clocks.

 

[FrankSchwab]

Use the 555, create a 100 Hz signal, and divide by 2. Perfect 50% duty cycle.

/frank

 

[MrDudeMan]

how do you hook up crystal oscillators? ive looked everywhere, but i cant find instructions on how to actually use it in a circuit.

 

[PottedMeat]

Originally posted by: Bigsm00th
how do you hook up crystal oscillators? ive looked everywhere, but i cant find instructions on how to actually use it in a circuit.

you can just stick in somewhere in your feedback loop,
there are a few examples in here:
http://ww1.microchip.com/downloads/en/AppNotes/00826a.pdf

 

[itachi]

Originally posted by: Mark R
Crystal oscillator and binary divider

Use a 3.27680 MHz crystal and a 16 bit divider.

That crystal frequency looks odd, but is a standard value - it was specifically chosen for 50 Hz clocks.

i'd go with this one.. it's the simplest and most accurate. if you want a more configurable (and a hell of a lot more complex) method then u can look into using a pll.

 

[tom314]

bump

 

[brentkiosk]

You can power your circuit from a 9 volt wall wart supply. The current rating only has to be comfortably more than your circuit uses. The circuit will just draw what it needs - not the whole 1.5 A.

Sometimes those power supplies produce DC that's not real clean, and this can cause trouble but it probably won't.

You are using a DC supply - not AC - right?

 

[tom314]

Yeah, this is a DC supply and it is going through a voltage regulator to the rest of my circuit so hopefully it will be okay. I guess I will have to test it to make sure it still works with the supply, I was just worried that it would burn up the IC's in my design so I was a little afraid of trying without hearing some kind of confirmation. Thanks for the reply.

 

[Calin]

Just take into account that the voltage rating can be deceiving - your DC supply might generate 9V for a load of 0.1 to 1.3A, and 10V for a load of 0A, and 8V for a load of 1.5 A. Make sure your circuit is able to withstand the "9V" voltage you read with the DC power supply turned on and no load