Battery Charger using Radiated Emission from a CRT of a Color Television Set

This paper presented an empirical result of a technique to make use of energy generated from a display, a cathode ray tube (CRT) type, of a color television set. A battery charger circuit with no external power supply, excepted from the radiated emission, was used as a testbed. The energy of the radiated emission from the CRT was trapped using an 80-83 kHz resonant circuit and converted to a DC voltage with a current of about 100-250 muA. The current was boosted up by a current booster, a circuit that uses capacitors, called storage capacitors, as energy storages. When the capacitor was charged at some point, the circuit was triggered and the energy accumulated was discharged from the storage capacitor to charge a rechargeable battery. With this technique, the charging current could be boosted up to about 2 mA with charging voltage of about 6 V. The test was performed to charge two AA-size rechargeable batteries. Each battery was discharged before recharging using the proposed circuit by placing the battery charger on the sides of a 29-inch CRT. The batteries were recharged separately for two hours each and they could be used to drive a small-toy DC motor about 2-5 minutes