Help in simple PUT Oscillator

zhaniko93

New Member

• Mar 12, 2010

• #1

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.

 

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RCinFLA

Well-Known Member

• Mar 12, 2010

• #2

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

New Member

• Mar 13, 2010

• #3

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

Banned

• Mar 14, 2010

• #4

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

Perhaps you should try building one in real life?

 

zhaniko93

New Member

• Mar 14, 2010

• #5

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

 

ericgibbs

Well-Known Member

Most Helpful Member

• Mar 14, 2010

• #6

zhaniko93 said:

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

Click to expand...

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.

 

Last edited: Mar 14, 2010

Y

youser

New Member

• Feb 17, 2011

• #7

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