Programmable unijunction transistor oscillator circuit problem

Thread Starter

mdalieren

Joined Apr 17, 2016
7
Hello,
I tried to make a slow speed speed oscillation with a PUT but it doesn't work. Just, as soon as I gave the power (6V DC), LED flushes weakly and then light gone. Capacitor reaches 5.9 volt and it doesn't discharge. I don't find out why. Could you check the circuit and tell why it doesn't work? Thanks...
(All components work well individually and transistor is 2N6027)

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crutschow

Joined Mar 14, 2008
27,912
My simulation of your circuit did not work either until I reduced the 330kΩ resistor to 300kΩ (or less), so you might try that.
 

Alec_t

Joined Sep 17, 2013
12,249
Are you sure you have the pinout of the PUT correct? The cap should connect to the emitter. The anode should connect to the programming resistors.
 

Thread Starter

mdalieren

Joined Apr 17, 2016
7
It doesn't work either. It works as in the video I have attached. I have tried varied resistors as well but It never worked. Should I calculate value of Rg (R2*R3 / (R2+R3) and then do it again?
 

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crutschow

Joined Mar 14, 2008
27,912
Below is my LTspice simulation of the circuit working.
Of course that's no guarantee that the real circuit will work with the same values.

Try increasing the power supply voltage to see if that makes a difference.

upload_2016-7-23_13-24-51.png
 
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