Uni-junction transistor

The graph of  figure 1 shows relationship in between emitter voltage and current. v_E  is plotted on vertical axis and I_E  is plotted on horizontal axis. The region from v_E  = 0 to v_E  = V_P  is called as cut off region as no emitter current flows (except for leakage current). Once  vE exceeds peak point voltage, IE increases, but v _E decreases. Up to certain point usually know as valley point (V_V and I_V). This is called as negative resistance region. Beyond this, I_E  increases with v_E this is saturation region, which exhibits a positive resistance characteristic.

The   process   responsible   for   negative resistance characteristic is called as conductivity modulation. When v_E exceeds V_P voltage, holes from P emitter are injected into the N base. As the P region is heavily doped  compared  with  N-region, holes  are injected to lower half of UJT.

The lightly doped N region gives these holes a long lifetime. These holes move towards B₁ to complete their path by re-entering at the negative terminal of V_EE. The large holes create a conducting  path  between  the  emitter  and  the  lower  base.  These  increased charge  carriers represent a decrease in resistance R_B1, therefore can be considered as variable resistance. It decreases up to 50 ohm.

The diode threshold voltage decreases with the temperature and R_BB resistance increases with temperature as Si has positive temperature coefficient.

Email based Electronics Devices and circuits assignment help - homework help at Expertsmind

Are you searching Electronics Engineering assignment help expert for help with Uni-junction transistor questions?  Uni-junction transistor topic is not easier to learn without any external help?  We at www.expertsmind.com offers free lecture notes for Electronics Devices and circuits assignment help and Electronics Devices and circuits homework help. Live tutors are available 24x7 hours for helping students in their Uni-junction transistor related problems. We provide step by step Uni-junction transistor question's answers with 100% plagiarism free content. We prepare quality content and notes for Uni-junction transistor topic under Electronics Devices and circuits theory and study material. These are avail for subscribed users and they can get advantages anytime.

Why Expertsmind for assignment help

1. Higher degree holder and experienced experts network
2. Punctuality and responsibility of work
3. Quality solution with 100% plagiarism free answers
4. Time on Delivery
5. Privacy of information and details
6. Excellence in solving electronics engineering questions in excels and word format.
7. Best tutoring assistance 24x7 hours