I'm trying to use a 555 timer to generate a constant signal of 100Hz at a 97% Duty Cycle. Its also using a 12v input and output.

Is the 555 a good choice for this, or are their better easier options out there for trying to accomplish this?

 

If is only one frequency then I recommend you use a microcontroller that you can better control the duty cycle.
For example, an MCU Attiny13V can do this and cost less than 1$. The software I can do for free in few minutes. So, if you decide to call for a solution to the MCU, then tell me and I help you with the software.

For programming Atmel MCU I recommend PonyProg solution:

Schematic PonyProg use serial port:
http://www.lancos.com/siprogsch.html

and PonyProg software:
http://www.lancos.com/ppwin95.html

 

The 555 is probably a reasonable choice. You have a period of 10ms with an short portion of 300μs. Those are pretty comfortable numbers. It's been long enough since I worked with a 555 that I don't remember if the classic astable output has duty cycles more than 50% or less than 50%, but that is easily taken care of with an inverter on the output.

Now, whether the 555 is a better way to go compared to a cheap MCU, well that depends on the application, what kind of performance you need, how many you are going to make, how fast you need to get it up and running, what tools you have available to you, and so on and so on.

 

You can use CD 4093 chip and get a 50/50duty cycle using one gate. And uses less current,voltage. [URL="http://books.google.co.uk/books?id=42CiOxcbCxAC&pg=PA14&lpg=PA14&dq=cd4093+oscillator++circuit&source=bl&ots=2-B_YH6w8K&sig=EaN15tZaPBFGJq1mliqSvFCUQz4&hl=en&sa=X&ei=dtXvUanQA4WN0wXC04HgDg&ved=0CA8Q6AEwAw#v=onepage&q=cd4093%20oscillator%20%20circuit&f=false[/URL"] cd4093[/url]

 

My Cookbook

 

Or you could use the 74LS123 if the duty cycle needs to be precise, and you don't want to use a micro controller.

Data sheet - http://www.google.com/url?sa=t&rct=...vABMSB7yaNQjVWmiNImoPZg&bvm=bv.49641647,d.aWc

Application notes - http://www.ti.com/general/docs/lit/getliterature.tsp?literatureNumber=sdla006a&fileType=pdf

 

Is the 555 a good choice for this...

Yes, depending on what you mean by "constant". The 555 and its timing components will drift a bit, especially with temperature. You'd never notice if you're flashing an LED but it won't work for tuning an instrument or running a clock. (You'd use a quartz crystal oscillator for those.)

 

C1 = 1μF, R1 = 12k, R2 = 1.2k, calculates to 91.67% duty cycle at 100 Hz.

 

You can use CD 4093 chip and get a 50/50duty cycle using one gate. And uses less current,voltage. [URL="http://books.google.co.uk/books?id=42CiOxcbCxAC&pg=PA14&lpg=PA14&dq=cd4093+oscillator++circuit&source=bl&ots=2-B_YH6w8K&sig=EaN15tZaPBFGJq1mliqSvFCUQz4&hl=en&sa=X&ei=dtXvUanQA4WN0wXC04HgDg&ved=0CA8Q6AEwAw#v=onepage&q=cd4093%20oscillator%20%20circuit&f=false[/URL"] cd4093[/url]

So? He's not trying to get a 50% duty cycle, but rather a 97% duty cycle.