I am currently learning electronic on my own. And I have a question about the circuit below.
Given: 2N6027 is a programmable unijunction transistors. (I'm not sure if that is the right schematic for it)
Question: The objective here is to make the LED oscillates on and off. I have tried all of the three circuits below, but only Circuit 1 works. Why circuit 2 does not work? I believe the resistors R2 and R3 in circuit 1 are connected in series anyway right?
Why does the PUT's gate have to be in between R2 and R3?
Below are the pictures of the Circuit 1