# Multi-Unit Coupled Motion Hybrid Generator Based on a Simple Pendulum Structure
## 3 Results and Discussion
### Demonstration of MCM-HG Applications  
After independent testing of the eight power generation units, the overall performance of the MCM-HG was tested. To avoid mutual interference between the power generation  
Figure 4: The output performance of P-TENG and PENG. (**a**) The open-circuit voltage, (**b**) short-circuit current, and (**c**) short-circuit transfer charge of P-TENG at a frequency of 0.5 Hz and angle of 15\({}^{\circ}\); (**d**) the open-circuit voltage, (**e**) short-circuit current, and (**f**) short-circuit transfer charge of PENG at a frequency of 0.5 Hz and angle of 15\({}^{\circ}\).  
units, a rectification-before-parallel connection method was chosen to integrate all the units, as shown in the circuit diagram in Figure 5a. Based on previous work, an ideal voltage source and an ideal current source can be paralleled, with the TENG considered as a current source and the EMG used as a voltage source [29; 30]. When the TENG and EMG are paralleled and in phase, they can exhibit the large current characteristic of the EMG and the high voltage characteristic of the TENG. At a frequency of 0.5 Hz and a swing angle of 15\({}^{\circ}\), the current and voltage of the MCM-HG are shown in Figure 5b,c, with measured peak current and voltage values of 4.1 mA and 353 V, respectively. The transferred charge is shown in Figure 5d, with a maximum transferred charge of 1.5 uC. (This study did not consider the impedance matching and phase synchronization issues in the TENG-EMG parallel system, nor did it quantitatively analyze their impact on the system's output efficiency). The MCM-HG was used to charge capacitors, comparing the charging performance differences between individual units and the integrated system, as shown in Figure 5e,f. Figure 5e shows the charging curves of a single-side S-TENG, C-EMG, P-EMG, single-side PENG, and single-side P-TENG for a 47 uF capacitor. After 20 s, the capacitor voltages are 4.39 V, 1.72 V, 1.56 V, 1.47 V, and 1.33 V, respectively. The MCM-HG was used to charge capacitors of 47 uF, 220 uF, 470 uF, and 1000 uF. After 30 s, the capacitor voltages were 12 V, 7.2 V, 4.3 V, and 2.3 V, respectively. To further demonstrate the practicality of the MCM-HG, a 47 uF capacitor was used to power a calculator, and a 470 uF capacitor was used to power a thermo-hyrograph, as shown in Figure 5g-h (Videos S1 and S2). Additionally, we conducted durability tests on the devices. After 43,200 cycles, the transferred charge (Q) of the TENG decreased by 0.5% compared to the initial transferred charge (Q\({}_{0}\)), the transferred charge (Q) of the PENG decreased by 4.9% compared to the initial transferred charge (Q\({}_{0}\)), and the output current (I) of the EMG decreased by 5.5% compared to the initial output current (I\({}_{0}\)) (Supporting Information, Figures S6-S8). The experimental results indicate that these units can maintain good performance after a large number of cycles, demonstrating high durability.  
Figure 5: Circuit connection of MCM-HG, output characteristics, charging characteristics, and driving electronic devices. (**a**) Circuit connection of MCM-HG; (**b**) the open-circuit voltage, (**c**) short-circuit  
current, and (**d**) short-circuit transfer charge of MCM-HG at a frequency of 0.5 Hz and angle of 15\({}^{\circ}\); (**e**) charging properties of S-TENG, C-EMG, P-EMG, PENG, and PENG charging a 47 \(\mu\)F capacitor; (**f**) charging characteristics of MCM-HG; (**g**) charging a 47 \(\mu\)F capacitor to drive a calculator, and (**h**) charging a 470 \(\mu\)F capacitor to drive a thermo-hygrograph.