Category: Electronics
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Linear/Analog vs. Digital Integrated Circuits (ICs)
Linear ICs (LICs) also referred to as analog ICs are characterized by inputs and outputs that can take a continuous range of values. In addition, the outputs are generally proportional to the inputs. On the other hand, Digital ICs contain circuits whose input and output voltages are limited to two possible levels i.e. low or…
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PIN Diode – Features & Applications
PIN diode is characterized by fast low capacitance switching. A PIN diode is fabricated in a similar fashion to a silicon switching diode with an intrinsic region added between the PN junction layers. This generates a thicker depletion region, the insulating layer at the junction of a reverse biased diode. This results in lower capacitance…
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Schottky Diode – Features & Applications
Schottky diode is fabricated as a metal-to-N junction rather than a P-N semiconductor junction. Also referred to as hot-carrier diodes, Schottky diodes are characterized by fast switching times (low reverse-recovery time), low forward voltage drop (normally 0.25 to 0.4 volts for a metal-silicon junction), and low junction capacitance. The forward voltage drop (VF), reverse-recovery time…
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The Principle and Application of IMPATT Diode
The Impact Avalanche Transit Time (IMPATT) diode is a high power radio frequency (RF) generator that operates from 3 to 100 GHz. IMPATT diodes are manufactured from silicon, gallium arsenide or silicon carbide. An IMPATT diode is reverse biased above the breakdown voltage. The high doping levels produce a thin depletion region. The arising high…
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The Shockley Diode Features & Operation
The Shockey diode is a four layer sandwich of PNPN semiconductor material very similar to the SCR but without a gate as illustrated in the Figure 1.0 below: The Operation of Shockley Diode A Shockley diode can be turned ON by applying enough voltage between anode and cathode. This voltage will cause one of the…
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The Diac Features & Applications
Features of a Diac The diac is a two-terminal, semiconductor, bi-directional switching device. It can conduct in both directions. The diac closely resembles a PNP transistor without an external base terminal. Operation of a Diac The diac does not conduct except for a small leakage current) until the breakover voltage VS is reached, typically 20…
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Unijunction Transistor Features and Operation
The unijunction transistor (UJT) is a three terminal, single-junction device which exhibits negative resistance and switching characteristics totally unlike those of conventional bipolar transistors. The UJT consists of a bar of n-type having ohmic contacts designated Base 1 (B1) and Base 2 (B2) on either side of a single PN junction designated the emitter. An…
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The Varactor Diode
The varactor also termed to as varicap, is a diode that behaves like a variable capacitor, with the PN junction working like the dielectric and plates of a common capacitor. Because of this, the symbol of the varactor is as shown below: A varactor diode employs a PN junction in reverse bias and has a…
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Basic Features of a Hartley Oscillator
The primary LC oscillator circuit does not have the option of controlling the amplitude of the oscillations. A weak electromagnetic coupling between first inductive coil L and second inductive coil L2 results in insufficient feedback and the oscillations would eventually die away to zero. Equally, a strong feedback causes the oscillations to increase in amplitude…
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What is a Microprocessor Clock?
The CPU clock dictates how fast the processor can process the data, and a microprocessor having a clock speed of 3 MHz means that it can process data internally 3 million times a second at every clock cycle. The crystal quartz oscillator is the most appropriate frequency determining device in virtually all microprocessors, microcontrollers, PICs…