Good morning everyone or whatever it is when this gets read. It has been a while since I put together a 555 astable for anything. I threw this together today as a clock for another part of my project and as such I guess it will work, well, I know it will since all I need is a positive going pulse. What has me puzzled is the waveform. I more or less expected a square wave and closer to a 50% duty cycle with the components selected for R1 and R2. Values are as marked on the schematic and the pot is as close to 5K as I could set it. Scope time base is .2us per division. Vertical gain at 0.2V per div. That is the other point. I was expecting around 6 to 8 volts output, not less than one. The scope is an older type 422 Tektronix and working fine. I have had it since I closed my business and yes, it's old but then so am I I forgot, scope is connected across R2. Picture is on the second page of the PDF. Would anyone be familiar enough with 555 to comment on this? I have used them before and thought I knew what to expect. Oh, also I did change the 555 just to be sure. Same thing. Suggestions please. I can use this, just not what I wanted or expected. Okay, I got it but it was weird. Maybe a half dozen times in my 40 years of service I have run across bad capacitors. (I mean new ones I installed.) That was it, or more then likely, just marked wrong. Tried a different capacitor and now have a nice square wave at almost 12V. I'll put that down to learning and should have tried a different cap first.