Electronic Component Identification Capacitors • A capacitor is an electronic component that can be used to store an electrical charge. • Capacitors are often used in electronic circuits as temporary energy-storage devices. • Capacitance is measured in units of farads (F) and named after Michael Faraday, a British chemist and physicist who contributed significantly to the study of electromagnetism. Ceramic disk Monolithic ceramic Solid tantalum, polarized Dipped silvermica Radial aluminum electrolytic Mylar Axial aluminum electrolytic Mylar Capacitors: Types and Package Styles Ceramic Disc Capacitors Electrolytic Capacitors Mylar / Monolithic Ceramic Electrolytic Capacitors Capacitors: Types and Package Styles Surface Mount Tantalum Capacitors Surface Mount Ceramic Capacitors Size Comparison How To Read A Capacitor’s Value Disc Capacitors Code Tolerance A ±0.05% B ±0.1% C ±0.25% D ±0.5% F ±1% G ±2% J ±5% K ±10% M or NONE ±20% N ±30% Q −10%, +30% S −20%, +50% T −10%, +50% Z −20%, +80% 4 7 2 K First Digit Second Digit Third Digit Fourth Digit First Figure Second Figure # of Zeros Tolerance 4 7 00 K 4700 pF 10% Note: Units on Disc Capacitors are always in pico-farads Capacitor: Example Example: Determine the nominal value for the capacitor shown. Code Tolerance A ±0.05% B ±0.1% C ±0.25% D ±0.5% F ±1% G ±2% J ±5% K ±10% M or NONE ±20% N ±30% Q −10%, +30% S −20%, +50% T −10%, +50% Z −20%, +80% Capacitor: Example Example: Determine the nominal value for the capacitor shown. Solution: 10000 pF 10% Code Tolerance A ±0.05% B ±0.1% C ±0.25% D ±0.5% F ±1% G ±2% J ±5% K ±10% M or NONE ±20% N ±30% Q −10%, +30% S −20%, +50% T −10%, +50% Z −20%, +80% Electronic Component Identification Diodes Diodes are semiconductor devices, but are considered passive since they do not contribute any amplification or gain to a circuit. Anode Light-emitting diode (LED) Cathode Small signal detector or switching diode Zener diode Types of Diodes The semiconductor diode is very versatile. The many different types enable a variety of applications. These applications include small signal applications, high current, high voltage, different types of diodes for light emission and detection, fairly low forward voltage drops, and diodes to provide variable capacitance. Small signal diode Laser diode Light emitting diodes Photodiode PIN diode Schottky diodes Zener diode Diodes: characteristics and parameters Forward voltage drop (Vf)- An electronics device passing current will develop a voltage across it called the forward voltage drop. Peak Inverse Voltage (PIV) - This diode characteristic is the maximum voltage a diode can withstand in the reverse direction. Maximum forward current(IF) - When designing a circuit that passes any levels of current it is necessary to ensure that the maximum current levels for the diode are not exceeded. Leakage current (IR) - If a perfect diode were available, then no current would flow when it was reverse biased. It is found that for a real PN junction diode, a very small amount of current flow in the reverse direction as a result of the minority carriers in the semiconductor. The level of leakage current is dependent on a number of factors. The reverse voltage is one, but also temperature. Leakage current can rise appreciably with temperature. Electronic Component Identification Resistors • A resistor is an electronic component that resists the flow of electrical current. • A resistor is typically used to control the amount of current that is flowing in a circuit. • Resistance is measured in units of ohms () and named after George Ohm, whose law (Ohm’s Law) defines the fundamental relationship between voltage, current, and resistance. Resistors: Types and Package Styles Carbon Film Resistors Variable Resistors (potentiometer) 4 Bands Carbon Film Resistors 5 Bands Surface Mount Resistors Determining A Resistor’s Value Color Code • Resistors are labeled with color bands that specify the resistor’s nominal value. • The nominal value is the resistor’s face value. Measured Value • A digital multi-meter can be used to measure the resistor’s actual resistance value. Reading A Resistor’s Value Resistor Color Code Resistor Value: Example Example: Determine the value for the resistor shown. 18 Resistor Value: Example Example: Determine the value for the resistor shown. Solution: 10 x 100 5% 1000 5% 1 K 5% 19 Electronic Component Identification Inductors Values specified in henries (H), millihenries (mH) and microhenries (μH) A coil of wire that may be wound on a core of air or other non-magnetic material, or on a magnetic core such as iron powder or ferrite. Two coils magnetically coupled form a transformer. Wire gauge and physical size of the coil determine the current handling capacity. Inductors: Types and Package Styles Molded inductor & air-wound inductor Ferrite core toroidal transformer Adjustable air-wound inductor Air wound inductor Iron powder toroidal inductor Relays • Relays are electromagnetically operated switches. • Relays are used for motor control circuits, switching circuits and power switching. Switches • The pole is the movable part Single-pole single-throw switch Single-pole double-throw switch Double-pole single throw switch • The throw is the number of circuits that are affected differently during the switching operation Single-pole push-button switch(make) Single-pole push-button switch(break) Single-pole double-throw push-button switch Single-pole selector switch Electronic Component Identification Transistors A transistor is a component that has three pins. The type of the transistor can be determined by the model number, which is printed on the body. Collector Base Emitter Drain Gate Source 2N2222A in a TO-18 package 2N2222 in a TO-92 package 2SC2078 in a TO-220 package Transistor specifications There are a number of standard parameters that are used to define the performance of a transistor: Type number Case Material Polarity The type number of the device is an individual part number given to the device. Device numbers normally conform to the JEDEC (American) or Pro-Electron (European) numbering systems - see Related Articles under main left hand menu block. There is also a Japanese standard system for transistor numbering. Case style - a variety of case standard case styles are available. These normally are of the form TOxx leaded devices and SOTxxx for surface mount devices. Note it is also important to check the pin connections as they are not always standard. Some transistor types may have their connections in the format EBC whereas occasionally they can be ECB, and this can cause confusion in some cases. The material used for the device is important as it affects the junction forward bias and other characteristics. The most common materials used for bipolar transistors are silicon and germanium. The polarity of the device is important. It defines the polarity of the biasing and operation of the device. The two types are NPN and PNP. NPN is most common. It has higher speeds as electrons are the majority carriers and these have a greater mobility than holes. When run in common emitter configurations, the NPN circuits will use a positive rail voltage and negative common line, PNP transistors will require a negative rail and positive common voltage. Integrated Circuits (IC’s) 3 4 1 1) 8 Pin Solder Socket 6 2) 14 Pin Solder Socket 7 8 3) 14 Pin DIP IC 4) 8 Pin DIP IC 2 5) 40 Pin DIP 5 6) 14 PIN SOIC 7) 8 Pin SOIC DIP – Dual Inline Package SOIC – Small Outline Integrated Circuit PLCC - Plastic Leaded Chip Carrier 8) 44 Pin PLCC Electrostatic Discharge (ESD) Protection Ground your work surface Use an anti-static mat Ground your tools (i.e., soldering iron) Many irons are constructed with a grounded tip Ground yourself Use a wrist or ankle strap, but always include a series resistor of high value to avoid any shock hazard. Touch a grounded object before handling static sensitive components. Static electricity can severely damage integrated circuits, especially CMOS chips.