Design and production of a SCR simulation teaching demonstrator

Based on the study of physical characteristics of SCR,and by utilizing 555 harmonic oscillator associated with the CD4017 decimal counter,to design and produce a SCR simulation demonstrator.Such a presentation aid could not only help the students' mastery of the basic performance of the SCR,but also enrich the contents of the experimental teaching.Trough vividly showing the direction of the current flow in electronic components by LED diodes,it helps students to better understand the nature of the related components' internal characteristics,and to inspire the students' desires to explore,as to give a great effect to the role of teaching aids.