You may not think of salt and sugar as solids because when you see them in the kitchen they are such small particles. But each of these particles is as much a solid as a wooden table, a glass window, or a gold piece of jewelry. A solid is a collection of atoms or molecules that are held together so that, under constant conditions, they maintain a defined shape and size.
Pulse Width Modulation, or PWM, is a technique for getting analog results with digital means. Digital control is used to create a square wave, a signal switched between on and off.
The PWM charge controller is a good low cost solution for small systems only, when solar cell temperature is moderate to high (between 45Â°C and 75Â°C). MPPT. To fully exploit the potential of the MPPT controller, the array voltage should be substantially higher than the battery voltage.