2. A solid is rigid and cannot be compressed easily. Reason: Molecules are closely spaced and the intermolecular separation is very small which cannot be reduced further. 3. A solid does not diffuse into another solid easily. Reason: Intermolecular force of attraction is very strong. 4. A solid does not flow and can be stored in a container. Reason: Intermolecular fore of attraction is so strong that molecules do not flow and leave the surface of the solid. 5. A solid on hating usually changes into its liquid state.
To PWM, or not to PWM, That is the Question. Pulse width modulation (PWM) is a fancy term for describing a type of digital signal. Pulse width modulation is used in a variety of applications including sophisticated control circuitry. A common way we use them here at SparkFun is to control dimming of RGB LEDs or to control the direction of a servo motor.
Digital telephone lines use Time Division Multiplexing (TDM), a method of transmitting multiple digital signals over one communication media, to accommodate up to 24 voice conversations over one circuit. The most common digital telephone lines are T1 and Primary Rate Interface (PRI).1 vs. PRI. PRI divides a T1 digital signal into 24 channels of 64 Kbps capacity per channel. 23 of these channels can be assigned as one telephone call each, the equivalent of having 23 separate telephone lines. The 24th channel is used for signaling information and special features such as caller ID.