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Tri-state Driver
In digital electronics, a tri-state or three-state buffer is a type of digital buffer that has three stable states: a high voltage output state (logical 1), a low output state (logical 0), and a high-impedance (Hi-Z) state. In the Hi-Z state, the output of the buffer is effectively disconnected from the subsequent circuit. Tri-state buffers are commonly used in bus-based systems where multiple devices are connected to the same shared bus, because the Hi-Z state allows other devices to drive the bus without interference from the tri-state buffer. For example, in a computer system, multiple devices such as the CPU, memory, and peripherals may be connected to the same data bus. To ensure that only one device can transmit data on the bus at a time, each device is equipped with a tri-state buffer. When a device wants to transmit data, it activates its tri-state buffer, which connects its output to the bus and allows it to transmit data. When the transmission is complete, the devic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Electronics
Digital electronics is a field of electronics involving the study of digital signals and the engineering of devices that use or produce them. It deals with the relationship between Binary number, binary inputs and outputs by passing electrical signals through Logic gate, logical gates, Resistor, resistors, Capacitor, capacitors, Amplifier, amplifiers, and other Electronic component, electrical components. The field of digital electronics is in contrast to analog electronics which work primarily with analog signals (signals with varying degrees of intensity as opposed to on/off two state binary signals). Despite the name, digital electronics designs include important analog design considerations. Large assemblies of logic gates, used to represent more complex ideas, are often packaged into integrated circuits. Complex devices may have simple electronic representations of Boolean logic#Digital electronic circuit design, Boolean logic functions. History The binary number system was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Logic Level
In digital circuits, a logic level is one of a finite number of states that a digital signal can inhabit. Logic levels are usually represented by the voltage difference between the signal and ground, although other standards exist. The range of voltage levels that represent each state depends on the logic family being used. A '' logic-level shifter'' can be used to allow compatibility between different circuits. 2-level logic In binary logic the two levels are logical high and logical low, which generally correspond to binary numbers 1 and 0 respectively or truth values ''true'' and ''false'' respectively. Signals with one of these two levels can be used in Boolean algebra for digital circuit design or analysis. Active state The use of either the higher or the lower voltage level to represent either logic state is arbitrary. The two options are active high (''positive logic'') and active low (''negative logic''). Active-high and active-low states can be mixed at will: for ex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leakage (electronics)
In electronics, leakage is the gradual transfer of electrical energy across a boundary normally viewed as insulating, such as the spontaneous discharge of a charged capacitor, magnetic coupling of a transformer with other components, or flow of current across a transistor in the "off" state or a reverse-polarized diode. In capacitors Gradual loss of energy from a charged capacitor is primarily caused by electronic devices attached to the capacitors, such as transistors or diodes, which conduct a small amount of current even when they are turned off. Even though this off current is an order of magnitude less than the current through the device when it is on, the current still slowly discharges the capacitor. Another contributor to leakage from a capacitor is from the undesired imperfection of some dielectric materials used in capacitors, also known as ''dielectric leakage''. It is a result of the dielectric material not being a perfect insulator and having some non-zero conducti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Capacitance
Capacitance is the ability of an object to store electric charge. It is measured by the change in charge in response to a difference in electric potential, expressed as the ratio of those quantities. Commonly recognized are two closely related notions of capacitance: ''self capacitance'' and ''mutual capacitance''. An object that can be electrically charged exhibits self capacitance, for which the electric potential is measured between the object and ground. Mutual capacitance is measured between two components, and is particularly important in the operation of the capacitor, an elementary linear electronic component designed to add capacitance to an electric circuit. The capacitance between two conductors depends only on the geometry; the opposing surface area of the conductors and the distance between them; and the permittivity of any dielectric material between them. For many dielectric materials, the permittivity, and thus the capacitance, is independent of the potential ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PCI Local Bus
Peripheral Component Interconnect (PCI) is a local bus, local computer Computer bus, bus for attaching Computer hardware, hardware devices in a computer and is part of the PCI Local Bus standard. The PCI bus supports the functions found on a System bus, processor bus but in a standardized format that is independent of any given Processor (computing), processor's native bus. Devices connected to the PCI bus appear to a bus mastering, bus master to be connected directly to its own bus and are assigned addresses in the processor's address space. It is a parallel communication, parallel bus, synchronous circuit, synchronous to a single clock signal, bus clock. Attached devices can take either the form of an integrated circuit fitted onto the motherboard (called a ''planar device'' in the PCI specification) or an expansion card that fits into a slot. The PCI Local Bus was first implemented in IBM PC compatibles, where it displaced the combination of several slow Industry Standard Arc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pull-up Resistor
In electronic logic circuits, a pull-up resistor (PU) or pull-down resistor (PD) is a resistor used to ensure a known state for a signal. More specifically, a pull-up resistor or pull-down resistor ensures that a wire will have a high logic level or low logic level, respectively, in the absence of a driving signal. It is typically used in combination with components such as switches and transistors, which physically interrupt the connection of subsequent components to Ground (electricity), ground or to IC power-supply pin, VCC. A closed switch creates a direct connection to ground or VCC, but without a PU or PD, when the switch is open, the rest of the circuit would be left floating (i.e. it would have an indeterminate voltage), which is generally undesirable. For a switch that is used to connect a circuit to ground, a pull-up resistor (connected between the circuit and VCC) ensures a well-defined voltage (i.e. VCC) when the switch is open. For a switch that is used to connect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Light-emitting Diodes
A light-emitting diode (LED) is a semiconductor device that emits light when current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy in the form of photons. The color of the light (corresponding to the energy of the photons) is determined by the energy required for electrons to cross the band gap of the semiconductor. White light is obtained by using multiple semiconductors or a layer of light-emitting phosphor on the semiconductor device. Appearing as practical electronic components in 1962, the earliest LEDs emitted low-intensity infrared (IR) light. Infrared LEDs are used in Remote control, remote-control circuits, such as those used with a wide variety of consumer electronics. The first visible-light LEDs were of low intensity and limited to red. Early LEDs were often used as indicator lamps, replacing small Incandescent light bulb, incandescent bulbs, and in seven-segment displays. Later developments produced LEDs ava ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
