I had a quartz wall clock in my workshop that ran a AA battery power. The battery died so I decided that rather than buy a battery, it would be more fun to convert the clock from battery power to AC power.
Step 1: Tools
For this project, the only tools that you'll need are a soldering iron and (optionally) a hot glue gun.
Step 2: Parts
You will need:
(1) 5V power supply .. I used an old phone-charger .. these can be readily found at any thrift store
(2) 22uF caps rated for 10V or better
(3) silicon diodes .. I used 1N4936 because it's what I had lying around .. but most any silicon diode will do .. the forward voltage drop will vary slightly for different diode types, but this circuit is fairly tolerant of small voltage differences.
(1) 1K resistor .. the power rating doesn't matter much, the resistor will only need to handle milliwatts of power
Step 3: Schematic
Here is the schematic ..
Step 4: Point-to-Point Wire the Circuit
Just connect up the circuit as per the schematic. Keep the leads relatively short so the entire circuit will fit in the space that was previously occupied by the AA battery. Once wired, you should check the output voltage with a multimeter. It should be somewhere between 1.5V and 1.6V
Step 5: Hot-Glue the Circuit in Place
This is somewhat optional, but it's nice to encapsulate the circuit ..
Step 6: We're Done ..
Sit back and admire your work :)