http://img689.imageshack.us/img689/7084/ujte.jpg [Broken] This is a Relaxation Oscillator circuit with UJT. I need to A) Explain what is UJT, explain its relation ratio of η for the UJT, and explain what Vp is. And in B) Explain how does the circuit work, and what is the output (or turnout) of the circuit Trying to use my own words UJT is a uni-junction transistor that has a single emitter and two bases. As long as the voltage in the emitter is smaller than the breakthrough voltage (Vp) , the UJT acts as disconnection. When the voltage in the emitter gets to the same voltage as Vp, the resistance at the base is broken through B1, and when the voltage in the emitter drops to a minimal value Uv, UJT is back to cutoff. relation coeffcient - η = Rb1/(Rb1+Rb2) Vp is "peak voltage" or "breakout" voltage. When the voltage in the emitter arrives to Vp then the UJT opens up (broken though). (Hope I didn't lose anyone by now!) B) This circuit generates pulses. Its made out of UJT and a capacitor. The capacitor is loaded from the source and when it reaches Vp, the UJT opens up and current flows from the Emitter through B1.