a dual powered calculator

[rugedoll]

helo to u all i have a problem maybe u could help me i dont know how a 2 way solar/battery supply for calculator work?how do it swicthes?what are the compenents needed hope u could help me thanks for reading this peace out!!

[audioguru]

Hi Ruge,
Welcome to our forum.
A calculator's solar/battery supply probably uses a simple two-diodes OR gate. Each diode feeds the calculator's supply, with the solar cell at one diode and the battery at the other. The source with the highest voltage forward-conducts through its diode and the other diode is reversed-biased and therefore disconnects its source.

Beware!
Many cheap calculators have a label, or photocopy of a solar cell, instead of having a real one! They look good. How can you tell without removing the battery?

Why can I purchase a complete solar/battery calculator at a price that is much less than just its replacement battery? When its battery dies, throw it away and buy another one.
Just like my PC's printer. I can purchase another complete printer for less cost than just its replacement ink cartridges! Throw away printer?