原理圖圖所示電阻值按圖今天調(diào)試時(shí)遇下問(wèn)題:
1、當(dāng)CPLD _relay=0V(低電平)時(shí)測(cè)得RELAY兩端電壓19V與24V差別太大;測(cè)得R93兩端電壓4.22VR97兩端電壓0.67V;
問(wèn):經(jīng)計(jì)算三極管應(yīng)該完全飽和了會(huì)壓降多
2、當(dāng)CPLD_relay=3.3V(高電平)時(shí)測(cè)得RELAY兩端電壓17.8V理論上應(yīng)該0V;測(cè)得R93兩端電壓0VR97兩端電壓0.563V光耦3端0.565V;
問(wèn):時(shí)候還有電壓
3、拿走RELAY當(dāng)CPLD_relay=3.3V時(shí)測(cè)得R93兩端電壓0VR97兩端電壓0V光耦3端0.03V;