Can I use an electronic calendar battery with 3 volts instead of 4.2 volts?

-★ 1, and the button cell voltage is a multiple of 1.5 V or 1.5; The rechargeable battery is a multiple of 1.2, and the 4.2 V battery has not yet appeared ... It should be a rechargeable battery with a rated voltage of 3.6v(3.7) and a limit voltage of 4.2 V, right?

-★ 2. The battery with rated voltage of 3.6v(3.7) can be used completely. Even with a new 3 V battery, the voltage will be as high as 3. 3 volts .. but rechargeable batteries are suitable for high-current appliances, and the working current of electronic calendars is extremely small, and the self-discharge current of rechargeable batteries is greater than the working current, so the service time of rechargeable batteries is short and it is not applicable.

The timing of the electronic calendar is determined by the oscillation frequency of the crystal oscillator and the accuracy of the frequency divider (high-quality circuit and error trimming capacitor), regardless of the higher applied voltage.