An UJT used for triggering an SCR has the supply voltage

Home » Power Electronics and Drives » Power electronics and drives miscellaneous » Question

An UJT used for triggering an SCR has the supply voltage VBB = 25 V. The intrinsic stand off ratio, η = 0.75. The UJT will conduct when the bias voltage V_z is

1. 25 V
2. ≥ 18.75 V
3. 33.3 V
4. ≥ 19.24 V

Correct Option: D

υ_z = ηV_bb + V_D
= 0.75 × 25 + 0.5 = 19.25 V