Unijunction transistor trigger circuit

(1) Precautions for selecting a single-junction transistor ① When selecting a single-junction transistor, the reverse voltage U
    between its emitter and base (bi). b. . It must be greater than the external power supply voltage (synchronous voltage) to avoid breakdown.     ② It is necessary to correctly select the partial voltage ratio of the tube, the valley point voltage U, and the valley point current I. . In the trigger circuit , I hope to use a slightly larger Diao, U. Lower, J. , larger single-junction transistors , which will increase the output pulse amplitude and phase adjustment range.     ③When installing, try to avoid heating components.     ④When used as a relaxation oscillator, Ri, Rz, R and C must be selected correctly, otherwise the oscillation cannot be started.