Simply, I like to check things.
Harvesting power from radio waves. Some data.
This is an addition to this page.
We already know that we can get some amount of energy from radio waves. In this case, we suck out the energy from the cell phone provider. At a frequency of 750MHz I have a max, therefore, the antenna was made for this frequency.
The capacitor block (24x1500uF10V) allows me to average the power, and the voltmeter and the clock - for measurements.
Schematic diagram and other details you can get on the previous page. And now - the result, or how quickly the capacitor is charged from such an antenna.
The energy stored in the capacitor is equivalent to half the product of the capacitance by the squared voltage ( E (Joule) = .5 * C (F) * V (Volts) ^ 2 ), so:
Skipping the rest, we can say that the maximum power (about 1.4uJ/sec.) will be received when the voltage across the capacitor ~ 0.2-0.4V. This means that the DC-DC converter must be stable in this voltage range.
Now, with more real data,
we can say that in order to light a white LED, for 0.1 second (req.0.003J), it is
necessary to wait until this energy accumulates in the capacitors. And it will take ... 36 minutes.
In case of questions - address is below.