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A PIN diode RF microwave switch. Under zero- or reverse-bias (the "off" state), a PIN diode has a low capacitance. The low capacitance will not pass much of an RF signal. Under a forward bias of 1 mA (the "on" state), a typical PIN diode will have an RF resistance of about 1 ohm, making it a good conductor of RF. Consequently, the PIN diode ...
A PIN diode has a central un-doped, or intrinsic, layer, forming a p-type/intrinsic/n-type structure. [42] They are used as radio frequency switches and attenuators. They are also used as large-volume, ionizing-radiation detectors and as photodetectors. PIN diodes are also used in power electronics, as
Figure 2.Greinacher circuit. The Greinacher voltage doubler is a significant improvement over the Villard circuit for a small cost in additional components. The ripple is much reduced, nominally zero under open-circuit load conditions, but when current is being drawn depends on the resistance of the load and the value of the capacitors used.
ASCRs are used where either a reverse conducting diode is applied in parallel (for example, in voltage-source inverters) or where reverse voltage would never occur (for example, in switching power supplies or DC traction choppers). Asymmetrical SCRs can be fabricated with a reverse conducting diode in the same package.
GTO thyristors suffer from long switch-off times, whereby after the forward current falls, there is a long tail time where residual current continues to flow until all remaining charge from the device is taken away. This restricts the maximum switching frequency to about 1 kHz. It may be noted, however, that the turn-off time of a GTO is ...
If connected in series with the circuit it simply prevents reversed current, but if connected in parallel it can shunt the reversed supply, causing a fuse or other current limiting circuit to open. All semiconductor diodes have a threshold voltage – typically between 0.5 volt and 1 volt – that must be exceeded before significant current ...
Parallel resistance is illustrated by the circulatory system. Each organ is supplied by an artery that branches off the aorta. The total resistance of this parallel arrangement is expressed by the following equation: 1/R total = 1/R a + 1/R b + ... + 1/R n. R a, R b, and R n are the resistances of the renal, hepatic, and other arteries ...
Trimming capacitors can be multi-plate parallel-plate capacitors with a dielectric for between plates for increased capacitance. However, at SHF only very small values of capacitance are needed. Presets at these frequencies are commonly a glass tube with plates at either end.