MindMap Gallery Semiconductor diodes and application circuits
This map is a knowledge mind map about semiconductors. Its content mainly involves diodes and circuits. This map explains semiconductor diodes and application circuits from the basics of semiconductors, semiconductor diodes, application appliances of semiconductor diodes, and special diodes.
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This template, created with EdrawMind, provides a structured workflow for weekly coordination meetings focused on MEP (Mechanical, Electrical, Plumbing) pipeline layout. It follows a four-stage cycle: starting with Issue Identification (Clash Detection) to detect pipeline conflicts, moving to Meeting Agenda preparation to define discussion topics, then On-site Discussion to review and resolve issues on the construction site, and finally Resolution & Update to document solutions and track progress. This template can be reused to standardize MEP coordination processes, ensuring clear communication, efficient problem-solving, and smooth construction progress.
This template, created with EdrawMind, outlines a quarterly checklist for preparing materials for green building certification. It is divided into four sequential quarters: Q1 focuses on Basic Material Preparation, including collecting project approval documents and compiling self-assessment reports; Q2 covers Technical Data Improvement, such as organizing energy consumption calculation books and preparing green construction proof materials; Q3 involves On-site Inspection Preparation, including organizing construction process materials and verifying certification standards; and Q4 is for Formal Application, which includes completing online reporting and cooperating with expert on-site reviews. This template can be reused to systematically prepare for green building certification, ensuring all requirements are met and the process is efficient.
This template, created with EdrawMind, provides a comprehensive framework for daily monitoring of deep foundation pit construction. It covers six key monitoring areas: Retaining Wall Top Displacement, Settlement of Surrounding Buildings, Groundwater Level, Pit Bottom Heave, Support Axial Force, and Data Summary & Analysis. Each section specifies monitoring points, frequency, and warning values to ensure safety. The template can be reused to standardize monitoring practices, track structural stability, and trigger immediate alarms if warning thresholds are exceeded, thus mitigating risks during foundation pit construction.
Chapter 1: Semiconductor diodes and application circuits
1. Semiconductor Basics
Covalent bond structure: the atomic structure of a single crystal formed by purification of elements such as silicon
Conductive properties: doping properties, thermal properties, photosensitive properties
Intrinsic semiconductor: a completely pure, structurally intact semiconductor crystal (free electrons and holes are generated due to thermal effects/intrinsic excitations)
Magazine Semiconductor
N-type semiconductor
Incorporation of pentavalent elements such as P (donor impurity)
Free electrons are majority carriers and holes are minority carriers
Donor impurities provide electrons, positively charged, positive ions
P-type semiconductor
Incorporation of trivalent elements such as B (acceptor impurity)
Free electrons are minority carriers, holes are majority carriers
The hole of the acceptor impurity captures the electron and is negatively charged, a negative ion.
PN junction
P-type semiconductors and N-type semiconductors are made on a silicon plate using different processes, and a thin layer with special physical properties is formed at the interface. Stable space charge region, high resistance region, depletion layer
Formation: concentration difference - diffusion movement of multicarriers - magazine ions form a space charge region - the space charge region forms an internal electric field (the internal electric field promotes the drift of minority carriers and prevents the diffusion of multicarriers) - reaches dynamic balance (diffusion current = drift current, the total current is 0)
One-way conductivity
Forward voltage (forward bias) Up>Un: The external electric field weakens the internal electric field, promotes the diffusion of majority carriers, and hinders the drift of minority carriers. The space charge area becomes narrower and the PN junction has low resistance (the internal electric field points from positive ions to negative ions)
Reverse voltage (reverse bias) Up<Un: The external electric field strengthens the internal electric field, hindering the diffusion of majority carriers and promoting the drift of minority carriers. The space charge region becomes wider and the PN junction becomes highly resistive.
Current equation (not important): Ut=26mV at room temperature
Voltampere characteristics
Forward conduction: overcoming dead zone voltage 0.5/0.1V; conduction voltage 0.7/0.2V
reverse cutoff
Reverse breakdown: breakdown voltage Ubr
capacitive effect
Barrier capacitance Cb: formed by changes in space charge region
Diffusion capacitance Cd: majority carriers are accumulated during the diffusion process.
Junction capacitance: Cj=Cb Cd. Ignore low frequencies and consider high frequencies
2. Semiconductor diodes
semiconductor structure
Semiconductor diode characteristic curves and parameters
Maximum rectified current If: the maximum forward average current allowed to pass through the conductor diode during long-term operation. If it exceeds the limit, it will be easily damaged.
Reverse breakdown voltage Ubr
Maximum reverse working voltage Urm=1/2Ubr
Reverse current Ir: leakage current, saturated leakage current is Is
Maximum operating frequency fm: it takes time for the diode to switch states
Interelectrode capacitance
DC resistance: DC power supply. Rd=Udq/Idq
Microvariable resistance: rd=Ut/Idq (Ut=26mV)
3. Application circuit of semiconductor diodes
Diode model
DC model
Acts on DC power supply and AC large signal circuits
ideal model
constant voltage drop model
polyline model
exponential model
communication model
Acts on AC small signal circuits
small signal model
Diode application circuit analysis
Rectifier circuit: converts the input bipolar voltage into a unipolar output. Use ideal models. A diode acts as a switch and conducts electricity in one direction.
Limiting circuit: Use constant voltage drop model. The diode has one-way conductivity and the voltage remains unchanged after conduction. (Analysis method: Find a point to ground; disconnect the diode and analyze the voltage at both ends; then discuss whether it is on or off and the voltage to be found)
Switch circuit: The conduction and cutoff of the diode is equivalent to the on or off of the switch, thereby realizing some logical relationships (analysis method: first assume that it is on or off; discuss the voltage at both ends; whether the assumption is true; find the voltage to be found)
4. Special diodes
Zener diode
The breakdown state voltage of the voltage regulator tube is constant at Ubr=Uz. During reverse breakdown, when the current changes within a wide range, only a small voltage change is caused.
Application circuit
The function of the resistor: current limiting function, protecting the voltage regulator tube; when the input voltage or load current changes, through the change of voltage drop on the resistor, the error signal is taken out to adjust the working current of the voltage regulator tube, thereby stabilizing the voltage.
Analysis method: Assume that a steady voltage state is reached; compare the voltages at both ends.
Other special diodes
Photodiode
led