Capacitor as a Charge Well

This is simple experiment I conducted to see effect of capacitor as a charge well/ charge pump to provide current burst in intervals.

I had an old cell phone battery and wanted to use it for running my small alarm clock which works on single AA battery. Now a look at datasheet of battery shows capacity of 1100 mAh. I assumed it lasts for 6 months.

So,
$\begin{aligned} 6 m o n t h s & = 180 * 24 h r s \\ = 4320 h r s \end{aligned}$

which means, clock requires a current of
$\begin{aligned} I & = 1100 / 4320 m A \\ = 255 μ A \end{aligned}$

The cell phone battery has voltage of $3.2 V$ . Instead of putting clock in parallel with a voltage divider, I put it in serial with a potentiometer of $5 k Ω$ .

Now I turned the pot to find maximum resistance at which clock still runs. It turned out to be $\approx 1 k Ω$ . But just the resistance with battery would draw $\approx 3.2 m A$ . Which could mean:

1. Clock has huge resistance of $11.5 k Ω$ or,
2. Clock has some lower resistance, but need intermittent current bursts.

Second option above looks more likely since clock involves mechanical movement after each second.

This gives a good opportunity to verify role of capacitor as charge well. So, initially I added a capacitor of $100 μ f$ in parallel with clock. After this addition, clock would run for $4 - 5$ seconds and stop with second hand vibrating in situ.

I thought this might be due to excess capacitance, so replaced the capacitor with $1 μ f$ .

Now it started working smoothly. So again I tried to turn the pot till clock stops working. As expected, maximum resistance now increases to $1.9 k Ω$ .

Link: https://anondissector.blogspot.com/2015/01/capacitor-as-charge-well.html