1. SMD Resistors
SMD
resistors are basic surface mount components that limit the current passing
through them. "R" stands for resistance, and the unit of
resistance is Ohm (Ω). 1KΩ equals to 1000Ω, 1MΩ equals to 1000000Ω.
There are two methods to indicate the
resistance value on the SMD resistors' appearance.
1. In
Arabic numbers: the first two numbers indicate the absolute numbers of the
resistance value, and the last number means the power of 10.
For example, 103 means 10000Ω, 391 means
390Ω, 473 means 47000Ω.
2. In
a combination of Arabic numbers and R: the Arabic numbers before the R stand
for the whole part of the resistance value, and those after the R stand for the
fractional part of the resistance value.
For example, R100 means 0.100Ω, 5R60 means
5.60Ω, 30R9 means 30.9Ω.
Classification of SMD resistors: according to
the use differences, there are normal resistors, precision resistors, power
resistors, high voltage resistors, high-resistance resistors, and high-frequency
resistors.
SMD
capacitors are PCB parts consisting of two metal pieces separated by an
insulator and mainly used to store energy. "C" stands for
capacitance, and the unit of capacitance is Farad (F).
The unit F is too big for SMDs' capacitance,
and we usually use the smaller unit μF, nF, pF. 1μF equals to 1000nF, 1nF
equals to 1000pF.
There are two methods to indicate the
capacitance value on the SMD capacitors' appearance.
1. Directly denote the capacitance and
working voltage on the capacitors, for example, 10μF/16V.
2. In a combination of Arabic numbers and
working voltage: the first two numbers indicate the absolute numbers of the
capacitance value, and the last number means the power of 10.
For example, 107 means 10 × 10^7pF (= 100μF),
225 means 22 × 10^5pF (=2.2μF)
Besides, on SMD capacitors, the capacitance is denoted by a combination of numbers and a letter.
Classification
of SMD Capacitors
Ceramic capacitors: made up
of a ceramic insulator with two terminals sprayed with silver then sintered. On
SMD capacitors, C.CAP stands for ceramic capacitors.
Aluminum electrolytic capacitors
aluminum
strip (as the positive electrode) covered with an oxide film (as the insulator)
plugged in it.
Tantalum electrolytic capacitors
Tantalum electrolytic capacitors: made up
of tantalum or niobium (as the positive electrode) and dilute sulfuric acid (as
the negative electrode), the oxide film covered on tantalum or niobium as the
insulator. TAN.CAP or TC stands for tantalum
capacitors.
SMD Inductors
SMD inductors are basic electronic components
that convert electrical energy into magnetic energy and store it. Inductors are
made up of an enameled wire winding around an insulator. "L"
stands for inductance, and the unit of inductance is Henry (H). 1H equals to
1000mH, and 1mH equals to 1000μH.
The method to indicate the inductance value on
the SMD inductors' appearance is below.
In Arabic numbers: the first two numbers
indicate the absolute numbers of the inductance value, and the last number
means the power of 10.
For example, 470 means 47H, 101 means 100H,
100 means 10H.
SMD Diodes and SMD
Triodes
SMD diodes are unidirectional conductive
electronic components. Diodes are also polar components, and the positive and
negative electrodes can't be reversed. When currents flow from the positive
electrode, the diode's resistance is extremely small. Vice versa, the
resistance is extremely large. CR or D stands
for diodes.
On SMD diodes, the terminal printed with lines is the negative electrode.
SMD triodes
SMD triodes are control components that amplify
currents. Q stands for triodes.
SMD ICs
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SMD ICs are surface-mounted integrated circuits that integrate components such as diodes, resistors, capacitors, inductors on an extremely small semiconductor then packaged. According to the packaging differences, the integrated circuits include PLCC, PPGA, PQFP, QFP, BGA, CSP, SSOP, etc.
Crystal Oscillators
An SMD crystal is a quartz piece with two
terminals polished and sprayed with a silver film. When an IC is packaged with
the quartz piece to form the oscillation circuit, it is an SMD
oscillator. Y stands for crystal oscillators.
SMD crystal oscillators provide basic clock
signals for the system.
On a component, if you see a combination of numbers and HZ or Z, that is a crystal oscillator.
SMD Connectors
SMD connectors provide temporary or permanent
electrical connections for circuits, and they are usually used in pairs.
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