LM741 as comparator

[blacktarantula]

Hello,
can someone help me here? how can I use LM741 as comparator in my circuit?
the comparator should compare 2 sources (240V ACs), and choose the highest as an output. Plz help me.

thnx

 

[alec_t]

Are the two sources locked in phase?

 

[blacktarantula]

sorry but i think not. because of source is from Grid supply and another from inverter (feed from battery).

 

[alec_t]

Use transformers to get isolated low voltages, say 6VAC, from each source. Rectify and smooth both low voltages to get, say, +7V and -7V from source A and +7V from source B. Use the +/- 7V from A as power rails for an op-amp. Tap off a fixed fraction of the A + voltage and apply to the non-inverting input of the amp. Tap off the same fraction of the B + voltage and apply to the inverting input of the amp. The amp output will approach either rail voltage according to which of A and B is the greater.

BTW, a purpose-built comparator IC would be better than a 741 for this.