Many years ago a Unijunction transistor or Programmable unijunction transistor (PUT) was used to make an oscillator but they might not be available today.
Two transistors can make an oscillator like this:

 

Many years ago a Unijunction transistor or Programmable unijunction transistor (PUT) was used to make an oscillator but they might not be available today.
Two transistors can make an oscillator like this:

Thanks. I have just ordered a pack of 555 timers. Give one or more of them a shot. But I will try and create that circuit. I think I have the parts it needs or there abouts.

 

Many years ago a Unijunction transistor or Programmable unijunction transistor (PUT) was used to make an oscillator but they might not be available today.

Yup, the are still available such as here.

 

BTW. While I have your attention. I did contact the one of the mods with this question but they didn't get back to me. How do I list all my previous postings on this site. My posting history if you will. It would be nice to be able to list them and go back and update the threads that people have contributed to. Is that possibe? I have had a good look around but I can't see a way of doing that.

 

How do I list all my previous postings on this site.

In the blue interface, you can click on your member name:

 

In the blue interface, you can click on your member name:
View attachment 198709

I have an orange interface. Not blue. Can you post the url to that page?

 

In the blue interface, you can click on your member name:
View attachment 198709

I found it. It's still orange though and it's a different layout to what you have posted. But I got it now. Thanks.

 

Below is the LTspice simulation of a 2N6027 PUT (programmable unijunction transistor) oscillator circuit (as AG mentioned).
It generates a short (≈200ms) pulse through LED D1 about every 2.5s, for the component values shown.

 

Hello Crutschow,
Your last attachment 198734 and most of your other numbered attachments give me an "Error 404 The page you requested does not exist."
My attachments are thumbnails with no number on them and they work fine.

 

Hello Crutschow,
Your last attachment 198734 and most of your other numbered attachments give me an "Error 404 The page you requested does not exist."
My attachments are thumbnails with no number on them and they work fine.

I'm seeing the same thing here.

 

Corrected the attachment in post #48.
Yes, when I refreshed the page, my attachment became unviewable.
Don't know what happened as usually my posted screenshots are fine(?).

 

most of your other numbered attachments give me an "Error 404 The page you requested does not exist."

What other attachments where?

 

What other attachments where?

Sorry, I can't remember where.

 

UPDATE:
Got it working. I had to rethink the layout and do a lot of investigation of voltages and voltage drops around the circuits to figure out what was going on and, as it turns out, there are issues when it come to discharging capacitors through the BE junctions of BJTs.

Anyway, here's the outcome. Needs a bit more work though. Using two different sources for the two transistors' base pins.
I need to feed them off of one source. But that's no big deal.

Thanks for the input all.

http://www.smegateway.co.uk/SMEgateway/videos/flashingledtran.mp4

 

UPDATE:
Got it working. I had to rethink the layout and do a lot of investigation of voltages and voltage drops around the circuits to figure out what was going on and, as it turns out, there are issues when it come to discharging capacitors through the BE junctions of BJTs.

Anyway, here's the outcome. Needs a bit more work though. Using two different sources for the two transistors' base pins.
I need to feed them off of one source. But that's no big deal.

Thanks for the input all.

http://www.smegateway.co.uk/SMEgateway/videos/flashingledtran.mp4

Hard to see what you've got on the breadboard. Can you share a schematic of the working circuit?

 

Hard to see what you've got on the breadboard. Can you share a schematic of the working circuit?

Sure. I will do the schematic when I'm finished. I want to make it single power source and I've ordered some smaller pots too to vary the resistances in the RCs. Then I'll sort out the schematic. The next version will be using a 555 timer.

 

You want an oscillator circuit that has a very low on-off frequency. Your extremely simple circuit does not do that.

I would use a logic Schmitt-Trigger inverter to make an oscillator and a Cmos Logic IC can make a very low frequency and use a very low power supply current powering it. Some people will use a 555 timer or a Cmos 555 timer IC to make an oscillator.
Look at them in Google.

My 555 timers arrived. Took about 4 minutes to flash an LED with one. Whatan incredible little IC. Going to have some fun with them. Thanks for the tip.