Rx is a resistor. In circuit diagrams, there are many resistors, numbered sequentially, such as R1, R2, …
Cx is a non-polar capacitor, used as an anti-interference capacitor at the power input.
IC refers to integrated circuit modules.
Ux is an IC (integrated circuit component).
Kx is ??? different manufacturers have different definitions in their component libraries.
Tx is a test point (for factory testing).
Spk1 is a Speaker (buzzer, horn).
Qx is a transistor.
Jx is a Jack (for example, Audio Jack).
Y1 ??? different manufacturers have different definitions in their component libraries.
Additionally, there are CEx – electrolytic capacitors, CNx – capacitor arrays (several capacitors together), RNx – resistor arrays, CONx – connectors, Dx – Diodes, Hx – holes, JPx – Jumpers, Lx – inductors/magnetic beads, LEDx – Light Emitting Diodes, Xx – crystal oscillators.
Each manufacturer has its own component library, and the components used in circuit diagrams are drawn from this library (large manufacturers). For some uncommon components, such as CON, JP, the definitions may vary among manufacturers.
R (resistor)
FS (fuse)
RTH (thermistor)
CY (Y capacitor: high voltage ceramic capacitor, safety regulation)
CX (X capacitor: high voltage film capacitor, safety regulation)
D (diode)
C (capacitor)
Q (transistor)
ZD (zener diode)
T (transformer)
U (IC chip)
J (jumper)
VR (variable resistor)
W (voltage regulator)
K (switch type)
Y (crystal oscillator)
On circuit boards, you often see labels like R107, C118, Q102, D202, etc. Generally, the first letter indicates the component type, such as R for resistors, C for capacitors, D for diodes, Q for transistors, etc.; the second is a number indicating the circuit function number, such as “1” for the main board circuit, “2” for the power circuit, etc. This is determined by the circuit designer; the third and fourth digits indicate the sequence number of the same type of component on the circuit board.
R117: Resistor on the main board, numbered 17.
T101: Transformer on the main board.
SW102: Switch
LED101: Light Emitting Diode
LAMP: (indicator) light
Q104 (E, B, C): Bipolar transistor, E: emitter, B: base, C: collector
“If R117 is a resistor, then measuring it with a multimeter should show continuity, right?” It is not scientific to measure resistance directly on the circuit board; the measurement result will be smaller than the actual value, sometimes significantly so. It is best to solder a lead out first and then measure.
