Using this diagram and plugging in 1kohm for RA, 5.6kohm for RB, and 0.01uF for C I should be getting a frequency around 11.8k and a duty cycle of 55%. I'm inputting a 12V 1amp source. when I measure the DC voltage between pin 3 and ground I'm only getting 0.68V. Shouldn't I be getting somewhere around 6 Volts? (Half of 12)

 

Nevermind. I'm an idiot. I had pin 2 connected to pin 7 instead of 6.

 

Now it's not working again..... I have everything hooked up right.

 

Now it's not working again..... I have everything hooked up right.

What to you mean, again?
What happened between it working and not working?

 

What to you mean, again?
What happened between it working and not working?

I hooked it up to the gate of a mosfet to try and make the rest of the circuit and went back to measure the voltage and got 0.68 Volts again. So I disconnected it from the MOSFET and still got 0.68. I know for a fact everything is hooked up right. It would have to be the chip or a wire right? The power supply is still putting out 12 volts.

 

It would have to be the chip or a wire right?

If you are sure it is connected properly, then yes.
Measure all the 555 pin voltages and post them here.

 

If you are sure it is connected properly, then yes.
Measure all the 555 pin voltages and post them here.

I changed the resistors from 1k to 10k and 5.6k to 56k and the capacitor from .01uF to .001uF. it seems to be working now. I'm thinking RA was too low at 1K.

 

What meter range do you use to read the o/p of the 555?

Using AC range, you'll get 8.79V ac. But if you use DC volt then the voltage changes so fast, may be 0.68V dc is what you should get.



Allen

 

Using AC range, you'll get 8.79V ac. But if you use DC volt then the voltage changes so fast, may be 0.68V dc is what you should get.

Not necessarily true
Most low-cost multimeters are not accurate on the AC range above a few kHz (or lower).
And many meters will measure the average amplitude of an AC signal on the DC range due to an RC low pass filter on their inputs.

 

You might do an initial proof out of your circuit by slowing the frequency down to a fraction of a hertz so that you can see the changes directly with the meter (I'm assuming you don't have a scope or other means of seeing the waveform).