The term bootstrap has a number of meanings in electronics. // Electronics is the study of electron mechanics. ...

In classical analog designs, a bootstrap circuit is an arrangement of components used to boost the input impedance of a circuit by using a small amount of positive feedback, usually over two stages. This was often necessary in the early days of bipolar transistors, which inherently have quite a low input impedance. The need for such arrangements has largely been alleviated by the use of modern field effect transistor designs, except when ultra-high input impedances are required. Note that because the feedback is positive, such circuits usually suffer from poor stability and noise performance compared to a circuit that doesn't bootstrap. It has been suggested that this article or section be merged with Analog electronics. ... The input impedance or sometimes loading impedance of a circuit or electronic device is the impedance actually experienced by a signal which is connected to its input. ... It has been suggested that this article or section be merged with Feedback loop. ... A bipolar junction transistor (BJT) is a type of transistor. ... Assorted discrete transistors A transistor is a semiconductor device, commonly used as an amplifier. ... Large power N-channel field effect transistor The field-effect transistor (FET) is a transistor that relies on an electric field to control the shape and hence the conductivity of a channel in a semiconductor material. ...

AC amplifiers can use bootstrapping to increase output swing. A capacitor is connected from the output of the amplifier to the bias circuit, providing bias voltages that exceed the power supply voltage. Emitter followers can provide rail-to-rail output in this way, which is a common technique in class AB audio amplifiers.

Another meaning is in connection with the booting process of a computer or other complex system, where the underlying electronics must arrange for the orderly startup of the CPU and related electronics components. This is done long before the CPU is in a state where it can begin to execute software. Nowadays the bootstrap is coordinated by special integrated circuits that monitor the raw power supply and provide the relevant signals to enable the CPU and other chips accordingly. In computing, booting is a bootstrapping process that starts operating systems when the user turns on a computer system. ... A BlueGene supercomputer cabinet. ... Die of an Intel 80486DX2 microprocessor (actual size: 12×6. ... Integrated circuit showing memory blocks, logic and input/output pads around the periphery Microchips with a transparent window showing the integrated circuit inside. ... A wall wart style variable DC power supply with its cover removed. ...

In a typical car alternator, a DC field current is required before the device can produce any output. Once running, a small portion of the output is fed back to keep the field alive — this can be seen as a form of bootstrapping. The initial priming current is usually obtained from the vehicle's battery — if the battery is totally flat the alternator won't produce any output voltage to spark the plugs or recharge the battery (by push starting for example) since it will be unable to bootstrap itself. However, in practice, a battery will usually have enough residual charge to avoid this. Early 20th century Alternator made in Budapest, Hungary, in the power generating hall of a hydroelectric station. ... Direct current (DC or continuous current) is the continuous flow of electricity through a conductor such as a wire from high to low potential. ... Four double-A (AA) rechargeable batteries In science and technology, a battery is a device that stores chemical energy and makes it available in an electrical form. ...

In reference to a regional or national power grid, bootstrapping refers to the process of restarting generating stations and restoring power to the grid after a large-scale power outage or disaster. This is also referred to as cold starting or black starting. The process is required for reasons not dissimilar to the automobile case above: many power stations have AC generators which do not contain permanent magnets, and are incapable of starting to produce electricity unless they are fed some from an outside source to energize the coils and produce a magnetic field. Once running, they use their own output power for this purpose and are self-sustaining. Some power plants are designated within the grid as being capable of a cold start (either because they have main generators which contain magnets, or have smaller auxiliary generators which do and which are capable of bringing the main ones up), and these plants are brought on-line first, and their power output directed across the grid to other plants and used to start them. In this way, generating stations across the network can be progressively brought back up. Transmission towers Transmission lines in Lund, Sweden Electric power transmission, or more accurately Electrical energy transmission, is the second process in the delivery of electricity to consumers. ... Oil power plant in Iraq A power station or power plant is a facility for the generation of electric power. ... Tree limbs create a short circuit in electrical lines during a storm. ... Restoring power after a wide-area power outage can be difficult, as power stations need to be brought back on-line. ... An electrical generator is a device that converts mechanical energy to electrical energy, generally using electromagnetic induction. ... It has been suggested that this article or section be merged with Magnetism. ...