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電子儀器與元件使用須知 林秉勳 大部分內容取材自汪治平老師「 Working with Electronics 」講義.

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Presentation on theme: "電子儀器與元件使用須知 林秉勳 大部分內容取材自汪治平老師「 Working with Electronics 」講義."— Presentation transcript:

1 電子儀器與元件使用須知 林秉勳 大部分內容取材自汪治平老師「 Working with Electronics 」講義

2 Wires, heat-shrink tubes Resistors, capacitors, inductors, transformers Switches, relays Diodes and transistors Integrated circuits and sockets Varistors, fuses Light-emitting diode, neon lamps, meters Heat sink, mica sheet Circuit Elements

3 American Wire Gauge (AWG) number diameter (mm) resistance ohm/km

4 Color-Code of Resistors

5 Low-Power Resistor High-Power Resistor Large resistors are often made of long coil of conductors. Watch out the parasitic inductance!

6 10-Turn Variable Resistor 3/4-Turn Variable Resistor

7 Electrolytic (1  F-10mF, for low-frequency circuits, polar, leaking, temperature sensitive, should be used with ceramic capacitors in parallel) Tantalum (1  F-500  F, low-leakage electrolytic) Polyester (Mylar) (1nF-10  F, general purpose, temperature sensitive) Ceramic (10pF-0.1  F, high-frequency filtering, temperature sensitive) Polystyrene, polypropylene (10pF-10  F, high quality) Types of Capacitors

8 Electrolytic Capacitor Tantalum Capacitor

9 Polyester Capacitor

10 Polypropylene Capacitor Ceramic Capacitor

11 Inductor Transformer

12 Rotary Switch Relay

13 Transistor Diode Integrated Circuit

14 Tools Wire striper Soldering iron and solder Desoldering tool Multimeter Oscilloscope Drilling machine Punching machine

15 Soldering Iron Wire Striper Desoldering tool

16 Multimeter Oscilloscope

17 Screw drive with neon lamp Neutral Hot Ground Hot Neutral Electric Outlets

18 Circuit diagrams Symbols Simulation and layout software Circuit-board fabrication

19 resistor capacitor inductor switch ground transistor diode voltage source current source transformer operational amplifier variable resistor

20 fuse field-effect transistor Zener diode inverting amplifier NAND gate NOR gate AND gate OR gate variable capacitor AC power lamp quartz crystal

21 Soldering Solderable materials: Au, Ag, Cu, Sn Scraping off oxides Function of resin Bad contact Presoldering Desoldering

22 presoldering to ensure quality bad contact good contact Soldering iron should touch both surfaces.

23 Assembling Test boards Posts and angle brackets Test points Heat glue Wire stand Power line cramp Shielding Switch protection

24 Power Switches

25 Post Test Board Angle Bracket

26 Wire Stand Buzzer

27 FuseFuse Socket

28 Light-Emitting DiodeNeon Lamp

29 Meter Battery Holder

30 Heat Sink Heat Conducting Paste

31 RG58 Coaxial Cable RG174 Coaxial Cable

32 Power Line Cramp Cable Tie Heat Shrink Tube

33 SMA Connector SMA (SubMiniature version A) connectors are coaxial RF connectors developed in the 1960s as a minimal connector interface for coaxial cable with a screw type coupling mechanism.. The connector has a 50 Ω impedance. It offers excellent electrical performance from DC to 17 GHz. Ref:

34 SMB Connector SMB (SubMiniature version B) connectors are coaxial RF connector and are smaller than SMA connectors. They feature a snap-on coupling and are available in either 50 Ω or 75 Ω impedance. They offer excellent electrical performance from DC to 4 GHz. Ref:

35 RCA Socket RCA Plug

36 F Connector BNC Connector

37 MHV Connector The MHV (miniature high voltage) connector is a type of RF connector used for terminating coaxial cable. MHV connectors are presently considered by some as a safety hazard because of the possibility of high voltage on the exposed central pin when not plugged in, and because the ground connection is broken before the power connection when demating. The MHV connector is typically rated for 5000 volts DC and 3 amperes. MHV with RG-59U cable Ref:

38 SHV Connector The SHV (safe high voltage) connector is a type of RF connector used for terminating a coaxial cable. This insulation geometry makes SHV connectors safer for handling high voltage than MHV connectors, by preventing accidental contact with the live conductor in an unmated connector or plug. SHV connectors are used in laboratory settings for voltages and currents beyond the capacity of BNC and MHV connectors. Standard SHV connectors are rated for 5000 volts DC and 5 amperes, although higher-voltage versions (to 20 kV, 13 amperes) are also available. SHV5 with RG-59U cable SHV20 with RG-8U cable Ref:

39 LEMO Connector The LEMO, a miniature push-pull 50Ω coaxial connector on RG 316 cable, is used in the Nuclear Instrumentation Module (NIM) and Computer Automated Measurement and Control (CAMAC) standards used in instrumentation for nuclear and particle physics. The LEMO connector is used as a replacement for BNC connectors in high density designs. BNC connector Ref:

40 Electric-Field Shielding Use coaxial cables ( RG58, RG174) Use shielded connectors (BNC, LEMO, RCA) Use grounded metal case

41 Why We Need Grounding In electrical engineering, ground or earth can refer to the reference point in an electrical circuit from which other voltages are measured, or a common return path for electric current, or a direct physical connection to the Earth. In powered equipment, exposed metal parts are connected to ground to prevent user contact with dangerous voltage if electrical insulation fails. Connections to ground limit the build-up of static electricity when handling flammable products or electrostatic-sensitive devices.

42 Shielding and Grounding transformer 3000 VAC circuit case 110 VAC

43 Ground Contamination earth surface underground water hot neutral ground equipment Lab A Lab B leak

44 Supply and Grounding Order Put high-power units closer to the power supply. preamplifier anti-coupling circuit power amplifier power supply

45 Magnetic-Field Shielding Use twisted-pair wires to eliminate induction currents Use cases made of high-  metal Avoid ground loop, use single-point grounding

46 Function of Twisted-Pair Wires alternating magnetic field induced current alternating magnetic field induced currents cancel

47 Switch Protection spark inductive load 100Ω 0.05  F varistor solutions

48 Semiconductors P-type Si, Ge doped with B, Al, Ga, In N-type Si, Ge doped with P, As, Sb Current formed by moving holes Current formed by moving electrons

49 Working Principle of Diodes forward biasing P N holes electrons conducting reverse biasing P N holes electrons non-conducting

50 Working Principle of Transistors PN B (base) C (collector) E (emitter) B (base) C (collector) E (emitter) N electrons

51 Impedance of AC Circuit capacitance inductance definition

52 Passive Filters high-pass low-pass band-pass ViVi VoVo ViVi VoVo ViVi VoVo if resonance:

53 Differentiators and Integrators high-pass low-pass ViVi VoVo ViVi VoVo if

54 equivalent circuit of coaxial cables Impedance of Coaxial Cables Assuming the impedance of an infinite-long coaxial cable is Z, and the inductance and capacitance per unit length is L and C respectively, then the impedance of a cable of lengthε(→0) in series with an infinite-long cable is still Z. independent of

55 wrong method correct methods How to Connect Coaxial Cables R 1MΩ load signal source signal source 1MΩ load receiving end T-connector cable impedance, 50Ω for RG58 and RG174 receiving end receiving end receiving end 1MΩ load signal source 50Ω load receiving end receiving end

56 Input and Output Impedance voltage source current source Z in Z out

57 Impedance Matching Z in = Z out Z out transmitting power = Maximum transmitting power occurs at Z in

58 Parasitic Capacitance and High-Frequency Response R out CpCp R out the smaller the better parasitic capacitance VoVo ViVi

59 Compensation of High-Frequency Response R out CpCp R in CsCs compensating condition: compensating capacitor parasitic capacitor R out CsCs CpCp R in input output

60 DC Block and Low-Frequency Response CbCb R in R in the larger the better VoVo ViVi


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