where, P is the effective value of output power of HPWC and
R is the resistance of the load. Therefore, the effective power
of HPWC with Coil A at different working frequencies can be
calculated by the experimental data in Fig. 6, which is shown in
Table III. Effective power of 0.3mW, 0.7mW and 1.1mW are
gained from HPWC with Coil A connecting with a load of 62.
From the calculated results in Table III, it can be found that the
effective power of HPWC with Coil A also increases with the
working frequency of hand crank.