digital output modules plc, which has several types, characteristics

igital output modules plc, which has several types, characteristics
According to different driving circuit, the digital output module can be divided into the following three categories:
High-power transistors and FET type - mainly used to drive DC loads.
Triac type - mainly used to drive an AC load.
Small relay type - used to drive AC or DC load, a contact signal outputplc digital input.
Switch if there is merit flexible output relay output AC and DC load large, slow to respond shortcomings
Advantages of fast reaction transistor output, shortcomings DC output, current, voltage is small.