The main reason for signal isolation is to provide electrical isolation between the input and the output signal. isolation of analog signals is very important for industrial automation and medical applications. The isolation of the analog signals is really expensive because of the way it is done standard isolation method is by using optocouplers, capacitance, and transformer. Well, these isolators are used to isolate digital signals and the solution for this is we need to do the analog to digital conversion and then the isolation of the signal could be done.
Benefits of isolation are • Noise immunity will be improved • Removal of the ground loop • Common mode voltage rejection increased • We could protect expensive equipment from transient voltages
Isolation by Optocouplers This is the oldest and most commonly used method for digital isolation it can provide immunity to high voltages and to electrical and magnetic noises Optocouplers are the components which could connect two separate circuits by means of a light-sensitive optical interface it could do the isolation process between the input source and the output load by using light
Analog optocoupler
If there is one or more analog signal to be isolated it could be connected to multi-input ADC
Capacitive isolation It is done by capacitive coupling these type of isolator gives high data transfer rate and high transient immunity
OPTOCOUPLER TYPES
photodarlington and phototransistor are used in DC circuits while the Photo TRIAC and SCR to control the ac powered circuits