Help in simple PUT Oscillator

[zhaniko93]

Hi all.
I am new and I am reading the book "MAKE Electronics", where I met one circuit, made with Programmable Unijunction Transistor and author says that That was oscillator circuit, so I built it in Proteus and It isn't oscillating. I attached circuit photo and Proteus project so Please if anybody can, download files and give advice how to build the correct one. Thanks.

 

[RCinFLA]

A 2.2 uF discharge will not provide much of a flash. Something around 100 usec which you will not see. If you use a white LED the cap voltage at triggering may not be high enough to forward bias the white LED very much with the two diode drop of the unijunction. device.

 

[zhaniko93]

but when I try It with proteus, It says that voltage on diode is constant, it isn't oscillating. if this circuit is false, than can some1 give circuit project for oscillations with PUT?

 

[Hero999]

Has it ever occurred to you that Proteus might be the problem?

Perhaps you should try building one in real life?

 

[zhaniko93]

Can you give advice about software which might be better to simulate such circuits?

 

[ericgibbs]

Can you give advice about software which might be better to simulate such circuits?

hi,
Download the free version of LTspice also join the Yahoo LTspice users group.
There are LTS models available for UJT's.


EDIT:
You can also make a UJT using two transistors.

 

[youser]

I was searching PUT models, and encountered this page.
Answer to the quiz is: The LED needs a resistor in series.