Show me how to make a voltage regulator circuit down to 1.6Volts

I have a rechargeable hair trimmer/shaver that has a slowly dying internal battery. I'm thinking that it would be cool to convert it over to using AA sized batteries.

The eneloop, well all the AA rechargeable batteries are all bloody 1.2V not 1.5v like the non-rechargeable batteries. Why that is I do not know. That me because they will not work in my wireless keyboard.

Anyway. The shaver says 1.6V. One eneloop recharge battery is 1.2V, so this is well under the required 1.6V of the shaver motor.

But two batteries together are 1.2v+1.2v = 2.4v which will make the motor spin out of control and the shaver will shoot up my nasal cavity.

So I need to bring 2.4V down to the required 1.6v. I see you can use voltage regulators and a couple caps to do this.

1. When a fresh battery is 1.2v, how much will it be when it is empty? I will need to know this for the voltage drop value for selecting a voltage regulator, right.
2. Anyone recommend a part number of a regulator?
3. What about capacitors what size adn value would I need.
4. Why are normal batteries 1.5V but rechargeable ones 1.2V?

What current ?

You could try a simple diode in series with the battery - this will drop approx 0.6 to 0.7v which isn't far off what you're after.

Personally though I'd try it at 1.2 volt and see how it works. The NiMh rechargable batteries are between 1.2 and 1.3 volts for most of their working life before it falls quickly at the end of the charge. Normal 1.5v batteries are not 1.5v for very long. When you put a load on like a motor you may even find its running at less than 1.2 volts.

If the shaver is rated 1.6V then a single AA alkaline cell should run it ok; but, as picbits points out, not for very long.
Can't you just replace the dying rechargable bat, or try 1.2 as suggested?
I have a shaver intended to take 3 x AA alkaline cells (nominal 4.5V total) but it's perfectly happy with 3.6V (3 x 1.2V NiMH).

If you really need a 1.5V rechargeable then you might try the NiZn types.

A batteries (cell) voltage is a function of the chemistry inside of it. Different Anode-Cathode material pairs produce different voltages. Some chemistries lend themselves to recharging (secondary cells.) Some are not rechargeable (primary cells)

Read more here: https://en.wikipedia.org/wiki/Battery_(electricity)#Battery_chemistry

Well there is what looks like a aaa battery in there.