1 Reed switch is a sensing element. When the magnet is close, the normally open contact is closed and the contact resistance of the connected circuit is only 10 mA.
2 Usually the toy DC motor has a low operating voltage, although it can be started at 1.5~3V, but the starting current is large (1~2 amps), and the running current is about 500mA when the motor is no-load.
3 low-power silicon tube 8050, its collector maximum allowable current ICM can reach 1.5A, to meet the motor starting current requirements
4 bimetal composite switch, closed when hot
5 Usually a photoresistor, such as MG45, has a bright resistance when light is irradiated. A 2 to 10 kΩ photoresistor is an electronic component that is rapidly increased in light-conducting conductivity. The commonly used model is MG45-1. When the working voltage is 5V, the current should not exceed 2mA.
6 water resistance is about 50kΩ
7 under the normal circumstances, 8-10 mA or less frequency current of 50 milliamperes of DC current may be allowed to secure the body current general situation, body resistance can be considered in Europe 1000-2000
8 low voltage (5V) buzzer, its working current only needs ten milliamps
9 relay coil (JRC—21F) operating current is about 60mA, which is smaller than the operating current of the toy motor. It is more than the buzzer and LED operating current. The ultra-small small power relay is commonly used, the model is JRC-21F, the coil power supply voltage is 3V or 6V contact working DC 24V, 1A relay coil resistance from ten ohms (3 ~ 6v) ~ ten thousand ohms (220v) 24V about 1K multi-coil current is not generally less than 100m
The difference between the 10 LEDs and the common diode is that the forward voltage drop during conduction is relatively large, generally 1.5 to 2. V (normal silicon diode is about 0.7 V). LED operating current is generally 10 ~ 40mA
The 110,000 meter diode test measures the on-resistance of the voltage drop diode between one hundred euros or one thousand ohms.
12 If the tube is in the form of a common anode, then its driver stage should be an open collector (OC) structure. If the tube is in the form of a common cathode, its driver stage should be an emitter output or a source output circuit.
13 regulators are connected in reverse in the circuit. The reverse breakdown voltage of the Zener diode is called the stable voltage.
14 220V bulb resistance is about 1000 ohms (25 watt bulb resistance is about 2000 ohms, working voltage is 220 volts) current is 100 mA. Small bulb (3v-5v) resistance ten ohms current hundred milliamps
15 car starter starting current is 200 ~ 600A
16 motor coil resistance does not exceed 2 ohms current to Baan for 380V motor 1 kW corresponds to 2 amps
17 ignition coil primary coil resistance does not exceed 1 ohm secondary approximately kilo ohm
18 IC output capability output current at high level
19 74LS: 400uA (cannot drive LED) (output impedance (internal resistance) 50 ~ 250 ohms (calculated according to short-circuit current), the ability to load with load requires load input resistance greater than 12K (according to output high-level current calculation 400uA) The input resistance of LS is 250K (20uA is calculated according to the input high level input current)))
74HC: 4mA (output impedance (internal resistance) ten ohms? (calculated according to short-circuit current), the ability to load with load requires load input resistance greater than 1.25K (according to output high level current calculation 4mA) HC input resistance is 50M ohm (According to input high level input current, calculate 0.1uA)))
Current 74LS when output low level: 8mA 74HC: 4mA
IC output is equivalent to a power supply, the smaller the internal resistance of the power supply, the stronger the relative driving capability. Generally, the internal resistance of the power supply is less than 1 ohm. The intermediate circuit input resistance is relatively large, and the output driver stage resistance is large (light bulb, relay). Small (horn, nozzle)
For a common-shot triode, the input resistance is approximately Rb and the output resistance is Rc.
The emitter output input impedance is large Rb+(1+B)Re The output impedance is small< 20 electret microphone resistance is about 500 ~ 800 ohms output is 3 end. It integrates FET (impedance matching). Speaker resistance 2 ohms, 4 ohms, 8 ohms, 16 ohms Headphone resistance 20 to 600 ohms 21 oscilloscope's input resistance is 1M ohm Digital multimeter voltage input resistance 1M ohm measurement resistance output voltage 0.65V Diode gear output constant current source 1mA 22 for speakers Channels refer to channels of different frequencies. Active speakers are amplifiers combined with speakers. The connector of the earphone is a 3-core left channel right channel and ground 23 sensors have electrical signals (which need to be amplified and shaped) and do not generate electrical signals. 24 integrated op amp amplification from 10,000 to 100,000 so there is a short virtual input impedance so the input current is 0 25 Zener diode drive capacity does not exceed 1A The 26 counter can perform two functions, counting and dividing. Asynchronous counters: Slow flipping one by one. Synchronous counter: The flipping speed is fast at the same time. BCD (decimal) counter: (0 to 9). Binary counter (0 to 15). Ripple counter: Counting is relatively large, 7 levels, 14 levels, 21 levels 27 Transistor = Transistor Logic Array = OC Gate 9013(NPN) 9012(PNP) Maximum Ic 500mA Ib is micro-ampere Max Vceo 20V 8050 (NPN) 8550 (PNP) Maximum Ic 1.5A Ib is milliampere Max Vceo 25v 2003 (Transistor Array) (NPN) Maximum Ic 500mA Maximum Vceo 50v (just used as a switch is not used for amplification) 7407 (6 gate buffer driver OC gate) Maximum output 40mA Maximum Vceo 30v (small drive capacity) 28 4007 Forward current 1A (rated value) Maximum forward current 30A Maximum reverse voltage 700V Forward voltage drop 0.9v For rectifier clamp protection 4148 Forward current 300mA (rated value) Maximum forward current 2A Maximum reverse voltage 75V Forward voltage drop 0.7v For small signal occasions The voltage drop of the LED is between 1.5 and 2.5V. LED operating current is generally 10 ~ 40mA 29 7805 Maximum input voltage 35V can provide 1.5A current (typically 500mA) 30 optocoupler 4N32 input rated current 60mA maximum forward current 3A reverse voltage 6v Vceo 30V Ic 150mA The 31 transistors are divided into bipolar transistors and field effect transistors. The field effect transistor is divided into a junction field effect transistor JFET and an insulated gate field effect transistor. FET input resistance is large, output resistance is small 32 negative feedback: sampling from the collector of the post amplifier is voltage feedback Sampling from the emitter of the post amplifier is current feedback The feedback signal is connected to the base of the transistor and is connected in parallel. The feedback signal is connected to the emitter of the transistor and is connected in series. Parallel negative feedback reduces input resistance Series negative feedback input resistance increases Voltage negative feedback reduces output resistance Current negative feedback increases output resistance Advantages of the 33 differential amplifier compared to the direct cascade amplifier: suppression of temperature drift. The greater the Re, the better the temperature drift is suppressed. Constant current source is equivalent to a large resistance 34 The integrated op amp is too large. In order to increase the input range, it must be connected to the feedback form. 35 shot-level output and output efficiency is only about 20% Push-pull output output efficiency is up to 80% Dual power supply: output without capacitor Single power supply: output plus capacitor. Set successfully put LM384, 8W power output can be connected to 500 microfarad capacitors. 36 inverse proportional operation: voltage parallel negative feedback amplification - R2 / R1 input impedance R1 output impedance is small Non-proportional proportional operation: voltage series negative feedback amplification factor 1+R2/R1 output impedance large output impedance small Voltage follower: Like the emitter follower, the input impedance is large and the output impedance is small. Uo=Ui The amplifier can be used to form an active filter, a voltage source, and a current source. 38 op amps have negative feedback, then the op amp works in the linear region. Active filter, voltage source, current source The op amp has positive feedback, then the op amp operates in the nonlinear region limiter voltage comparator (no feedback). The zero-crossing comparator hysteresis comparator (positive feedback) precision shaping circuit (feedback loop plus diode) waveform generation circuit. 39 power rectification-filtering-regulation 78 series: the input and output voltage difference must not be lower than 3V 40 8051 generally refers to the 89c51 produced by intel, which refers to the 51 series products produced by Atmel. 41 single-chip reset circuit: use a 10u capacitor and 10K resistor to complete the addition of a 1N448. Reset time is not less than 5ms or 22u capacitor 1K resistor high level reset: capacitor close to the power supply. Low level reset: The capacitor is close to ground. 42 51 MCU addressing mode: immediate, direct, register (register is faster than direct, direct and register are equivalent to put data into a ram variable), indirect addressing (the address is placed in the variable, equivalent to c + + The pointer, in the address addressing, can only use R0 or R1 to store the searched data, etc. (R register can be used as a register to control the number of loops)), indexed addressing (for table lookup MOVC A, @A +DPTR)MOV DPTR, #TABLE (the meaning of the label in front of the label: the label is an address!! For example, TABLE is 100H #TABLE is the immediate number #100) 43 51 The DPTR is a 16-bit register that stores the address. Access to external ram must use A accumulator 44 SP should be initialized before use to indicate where the stack segment starts. For example, MOV SP, #5FH ORG indicates where the program segment starts. The 45 shift command can be used to perform a gondola test. 46 LJMP>AJMP>SJMP AJMP is a two-byte instruction. LJMP is a three-byte instruction. 47 CJNE: Compare two numbers after they are unequal and transfer (first judge whether they are equal, then you can judge whether they are large or small with JC jump) DJNZ: After subtracting 1 is not equal to zero transfer, used to control the transfer of the number of times Instruction: JB (transfer when bit is 1) JBC (bit is 1 transfer and clear 0 for query mode clear interrupt flag, no need to manually clear 0 when using interrupt mode) 48 When performing bit processing, CY (that is, the carry bit) is called "bit accumulator" and is equivalent to A in byte processing. There are many restrictions on the 49 counter/timer to run: 1. C/T switch 2. Tr switch 3. Gate switch (Gate=1, it is also controlled by Int1). Start T with SETB TR0. There are 4 ways of working: 0. 13 bits 1. 16 bits 2. There are presets (high 8 bits for preset, low 8 bits for counting, so the range is small), generally used for baud rate generator 3. Timer 0 is divided into two independent timers/counters. Generally, when T1 works in mode 2, T0 works in mode 3. Registers for T: TCON Control Timers and Interrupts TMOD is primarily used to control the operation of T. The timer is used in the interrupt mode when the interrupt is completed: 1. Action 2 to be implemented after the interruption. Re-preset the counter (equivalent to the work done automatically by mode 2). Set a soft count loop operation, output after multiple timings, which increases the timing time. 50 Registers for Interrupts: IE: Interrupt Master Switch IP: Interrupt Priority ECON SCON Interrupt program time cannot be greater than interrupt interval 51 communication direction: In serial communication, the one-way transmission method that can only send or receive the communication interface is called simplex transmission; and the two-way transmission of data between the two machines is called duplex transmission. In the duplex transmission mode, it is divided into half-duplex transmission and full-duplex transmission. Half-duplex transmission is that the two machines cannot transmit and receive at the same time. At any time, only the information can be sent or received. 52 serial port: Mode 1: Shift register mode Externally connected to a parallel shift register CD4094 74LS164, you can expand a parallel port 53 software removes the button jitter and finds that it is pressed again 10ms after the button is pressed. 54 The value of the program counter (PC) in the 8051 after power-on reset is '0000', so the program always starts from the '0000' unit. 55 carbon film resistor: Power is 1/6, 1/4W 1Ω～22M Accuracy 5% Cheap 1 to 2 cents Precision resistor Power is 1/6, 1/4W 1Ω～22M 1% higher accuracy 5 cents Oxide film resistance: 1~2W 0.1Ω～22M Accuracy 5% 5 cents Cement resistance: 5~50W 0.11~1K Accuracy 5% Less than 1 yuan Ceramic resistor: 50~200W 0.1Ω-1K Accuracy 5% Tens of dollars 2W high voltage resistor 270M Accuracy 5% 5 yuan Varistor Accuracy 5% Less than 1 yuan Exclusion (5 feet - 12 feet) 100Ω～1M Accuracy 5% 5 points / foot Adjustable resistance (sleeping. vertical) 100Ω-1M Accuracy 5% Less than 1 yuan Small power resistors are generally chosen for precision resistors because they are inexpensive. Generally select the resistance according to the power: 1 ~ 2W oxide film resistance 5 ~ 50W cement resistance 50 ~ 200W ceramic resistance (too expensive) 56 capacitor: Ceramic capacitor: 0.5p~0.1u Withstand voltage up to 30KV, generally 50V Polyester capacitor: 100p ~ 4.4u The withstand voltage is generally 50 ~ 100V, the highest is 630V Electrolytic capacitor: 0.1u ~ 220,000 u, withstand voltage, etc. 6.3v 10v 16v 25v 35v 50v 160v 250v 400v (no 15,20) Pressure is more than 100v, very expensive, even a few hundred dollars Tantalum capacitor: 0.1u ~ 100u withstand voltage up to 50V Similar to electrolytic capacitor Monolithic capacitor: 10p ~ 2u withstand voltage generally 50 ~ 100V Safety regulations for AC 250V 0.01u~2.2u Resin for AC 250V 0.1u～47u The smaller the capacity of the capacitor, the higher the pressure resistance: the size of the ceramic tile < monolith <polyester < 钽 < electrolytic 钽 and electrolysis are large-capacity capacitors. 57 diode: Rectification: 1N40 series (1A) 1N54 series (3A) 1N52 6A series (6A) Switch: 1N4148 Fast recovery: FR series (1A ~ 6A) FR10 * (1A) FR15 * (1.5A) FR20 * (2A) FR30 * () 3A FR60 * (5A) Very cheap no more than 5 horns Silicon rectifier bridge from 1A to 40A withstand voltage 100V ~ 1000V no more than 10 yuan Zener diode: 2CW 2DW 58 triode: too many models 2N (Japan, USA) B × × (Europe). Medium and small power (less than 1W current less than 1A voltage generally does not exceed 100V): 90 series 8050 8550 in the country half (power is slightly derived from 90) 2SC1815 2SC945 2N5400 2N5550 (higher withstand voltage over 100V) The medium power is relatively small (1~1.5W voltage is higher than 200V and the current does not exceed 0.5A). Used in color TV cameras. High power (5W or more) low withstand voltage (less than 100V current 10A or more): 2N3050 MJM2955 (for power supply expansion) Very little withstand voltage High withstand voltage (several hundred volts, current 2A or more): for color TVs and monitors 2SD820 2SD1403 (for power supply) 2SD951 (for line output) Regulated power supply: 78, 79 series (fixed output, maximum input voltage 35V output 5V ~ 24V) LM317 LM337 (output voltage adjustable 1.25 ~ 37V can provide 1.5V current, input and output difference can not be greater than 40V) LM350 (3A) TL431 can be used as a reference source because the output power is too small. 59 Optocoupler: 4N TLP PC MOC 60 DIP switch: It is generally used in the single-chip microcomputer to set the initial parameters, and does not change frequently. The switch is usually directly connected to the ground, and there is a pull-up resistor. When there is a pull-up resistor inside the microcontroller, it is omitted (p1.p2.p3 is a quasi-bidirectional port. When input, it is internally raised to a high level) XLF: Micro printer. Integrated infrared receiver: Integrates infrared receiving and amplifying, and can be compatible with TTL level signals from infrared receiving to output without any external components. The DM-162 LCD module can be directly connected to the microcontroller. ARP9600: Voice recording and playback chip. UPC1651 high gain high frequency amplifier integrated circuit for audio signals can be directly connected to the wire MOC3041: Optocoupler, triac 97A6: SCR TWH8778 (8751): Power fast, operating voltage 3 ~ 24V, switching current 1A. enter TTL compatible, can replace conventional relay LM324: Four integrated op amps HT7150: Power regulator maximum input voltage 24V output is 5V output current is only 30mA LA4425: The amplifier can drive 8 Euro 5W speakers. LM384 TDA2030 can drive 8 Euro 12W speakers LM386 61 LED digital tube display is very simple: 1 first convert the hexadecimal to decimal, put it in a, b 2 display code (no decoding circuit) 3 output from the output port 4 open control bits 5 delay 6 off control bits The 62 single-chip microcomputer directly drives the 8050 to be driven with a low level. The rated power of the 63 resistor is generally the maximum power, which is much less than this power when used. The power of other devices refers to the rated power, and the device should work near its rated power. Insufficient driving ability has two situations: 1 . The input resistance of the device is too small and the output waveform will be distorted. If the TTL level cannot drive the relay 2. The input resistance of the device is large enough, but it does not reach the power of the device. For example, a low-power amplifier can drive a high-powered speaker, and the speaker can sound, but the volume is small, but the output voltage is not large enough. 64 analog integrated circuits can be divided into four types: linear, nonlinear, power, and microwave (frequency over 300MHz). 65 famous chip manufacturers: Japan: NEC (Japan) HITACHI (Hitachi) TOSHIBA (Toshiba) MITSUBISHI (Mitsubishi) NATIONAL PANISONIC (Panasonic) FUJITSU (Fujitsu) SANYO (Sanyo) SONY (Sony) SHARP (Sharp) SANKEN (Sanken) JRC (JRC Series) ROHM United States: INTEL (Inter) MOTOROLA (Motorola) NATIONAL SEMICONDUCTOR (the national half logo is an F or a water wave) TI (Dexus Instruments produces TL series) SIGNETICS (Seigritix produces NE555 NE series) HARRIS (Harris is RCA (CA Series) GE INTERSIL three-in-one (production of ICL ICM series chips)) AD - PMI (analog device company AD OP DG ADG series) AMD SPRAGUA (Sprager produces ULN series) IR (International Rectifier Corporation) LT (LINAR TECHNOLOGY produces LT series) RATHEON (Raytheon produces RC series) CYPRESS SEMICONDUCTOR (icon is a cypress tree) Europe: PHILIPS (Philips) ST(SGS THOMSON) SIMENS (Siemens) Korea: SAMSVNG (Samsung) GOLDSTAR (高士达) DAEWOO (Daewoo) HYUNDAI (modern) Taiwan: UMC 66 74, 40 series of manufacturers are interchangeable. 61××, 62×× indicates ROM 27××EPROM 28××E2PROM 67 Universal Op Amps: LM741, LM833, LM324, LF411, LF347, LF358, TL071, TL081, MC34081, MC34071, MC33078, RC4558, RC4560, NE5532, AD711 68 comparator: analog to digital, and the output is TTL compatible. LM311, LM339 (239, 139), LM319 69 multiplier: can form a low-pass filter, frequency conversion, and lifetime measurement. . . . AD538 70 PC with DRAM (models start with 4 as 4164) SRAM with SRAM (starting with 62, 65, 66, 67 HM Hitachi's memory HY Hyundai GM Venus) EPROM has a small window (starting with 27) E2PROM (starting at 29) Flash ROM: fast access speed, power off 71 power supply: single-chip power supply type: fixed: 78 79 series adjustable: LM337 Voltage regulator ASIC: no power module, good stability, output voltage configuration LM723 Regulated by switching: TL494 SG3524 Reference source: The output current is small, and the reference voltage of AD is very high. AD580 LM113/313 72 analog switch: small signal switch, not a large current switch 406 in the 40 series and AD75 × × (performance is too expensive, no need) 73 V/F F/V is widely used in the radio field. The phase-locked loop is used in communication circuits and has complex applications. 74 drive array: ULN2003 (Sprag) 75 A/DD/A (ADC DAC series is manufactured in the country) AD574(A/D) AD7520(D/A) Sample and hold: LF198/298/398 76 PIC microcontroller is a microcontroller produced by General Instrument 77 Optocoupler: Toshiba's TIL Series Motorola's MOC Series The recognized 4N series is only a dozen. More than 78 laps (single turn) potentiometer: Mexico's BOVREN brand of 3006, 3296 power does not exceed 1W resistance 10 ohms ~ 5M ohms 79 zinc oxide varistor: suppress surge voltage and protect the circuit. 80 thyristor compared with the triode: the magnification is up to tens of thousands of power and can reach tens of amps and thousands of volts. 81 digital tube popular EDTECH products models start with LA LC LD LE LM LN and BSR BSG series 82 home appliance chip: European: DTA Series Toshiba: TA Panasonic: AN NEC : uPC Sanyo: LA Hitachi: HA HM   Toyo Electric Appliances: BA Mitsubishi: M SHARP: IX SONY: CXA Samsung: KA 83 digital multimeter: 3 and a half can be used oscilloscope: double trace 20M can Logic Analyzer: There are many channels for digital circuits that are rarely used Signal generator: the high frequency can reach 2MHz. Frequency meter: special measurement frequency Sweeper: measuring the frequency characteristic curve of the device Graphic instrument: Measuring transistor characteristic curve, because the quality of the triode is becoming more stable, it is of little use. Power meter, field strength meter, spectrum analyzer: very dedicated instrument Switching power supply is compared with ordinary power supply: small size, cheap, but anti-interference difference ripple is large 84 universal op amp (such as LM324, need + power) application 1 . Signal amplification, can replace the triode 2 . Signal multi-channel assignment, connected to the emitter follower form, large input impedance 3 . Bandpass filter for use in audio equipment, select different frequencies and process 4 . Comparator, the op amp does not connect to the feedback resistor. Comparator application: can be made into a voltage over limit indication. 5 . Monostable trigger: In fact, the capacitor is connected to the comparator form. Application of the 85 comparator (LM339): The LM39 output is an OC gate and requires a pull-up resistor. LM339 is mainly used for threshold indication, alarm, etc. The LM339 plus positive feedback forms a hysteresis comparator. It is also possible to compose an oscillator. 4060 is a counting/divider/oscillator. 6-inverter 4069 can be used as a square wave generator. 4047 oscillator 4033 decimal count / 7-segment decoder input pulse output coding needs to be driven 4544 BCD-7 segment decoding/driver input is 4-bit BCD code output is 7-segment code 4518 Two 4-digit BCD code counters Input is a BCD code with a pulse output of 4 bits 4017 counter/divider input is pulse output 10 channels, one pulse per channel 86 Using the temperature coefficient of the triode, it can be made into a temperature probe, and the triode is connected in the form of a diode. Both the base and the collector are connected together. The triode can be used with 3DG6. 87 design power is not a large power supply: transformer selection 220/15 (18), current 1.5A (3A determines the power of the power supply) Use off-the-shelf rectifier bridges (see capacity 5A is enough) or build them yourself with 4 diodes The filter capacitor is several thousand u Regulator circuit: After filtering, use 7805 to generate its own voltage 5V. Some LM337 is used to make the adjustable current is not big enough. It can be added to the transistor to expand 2N3055. 88 Y992: DC power supply, can output waveform with adjustable duty cycle, need to add crystal oscillator, drive capacity is only 10mA, can be made into waveform generator, oscillator. Square wave generator can be made with 6 inverter 4069 89 ICL7660, MAX870, MAX828 can turn +5V into -5V ICL7107 3 and a half AD to do the digital meter with the common anode LED 90 varactor diode (several hundred picofarads) varactor diode for radio channel selection. 91 infrared remote control: transmitter: 1 Encoder 2 oscillator 3 infrared launch tube Receiver 1 Decoder 2 Infrared Receiver. 92 LM35D integrated temperature sensor It is a combination of temperature sensor and amplifier circuit 93 power supply design filter capacitor size selection, generally around 1A in 2000 ~ 3000u 94 integrated temperature sensor, typical products are AD590, AD592, TMP17, LM135 The 95 triode drive is to directly drive the driving device to the collector (NPN), and the driving capability is affected by the transistor Ic. If the collector is added with a resistor and then output, the driving capability is affected by the resistance. The base and collector of the triode can be voltage-transformed with different voltages The emitter follows the form output output voltage is less than the input control pulse output voltage is affected by the input but the drive capability is strong 96 for NPN tube emission junction cut-off transistor cut-off Emitter junction conduction positive bias collector junction reverse bias triode amplification The emitter junction is positively biased and the positive junction is positive. The voltage at the saturation output of the transistor is not fixed. The output voltage is very low. 0 Therefore, when the collector junction is positively biased, Vce is small and the output maximum voltage is Vc. 1 When the emitter follows the form, the emitter junction is positively biased and the junction is reversed. Therefore, the output voltage in the amplification region is always Vb. This connection is not used as a switch drive as an output to increase the drive capability and cannot be level-shifted. 2 If both the emitter and the collector are connected to the resistor, the output point is at the collector output. When the transistor is turned off, the output Vc has an input signal. The output voltage of the transistor is Vb-0.7-Vb* (Rb/(Rb+rb+(1+β) )Re)), Re is not very small, the output is smaller than Vc and it is impossible to output 0 level. So this connection cannot be used as a switch In the case of NPN, the general Rb is generally larger than Rc Re. 3 The general connection collector plus a resistor (the resistor can be replaced by a drive device) is used as a switch. 97 Protel design is divided into 3 parts: schematic, generate network table, generate PCB 98 bipolar transistor is a current control device. Field effect transistor is a voltage control device divided into MOSFET (insulated gate) JFET (junction) 99 1 degree = 1 kWh 1 kW (power) = 1.36 hp Single-phase AC power for electric lamps and household appliances Motors of the same capacity Three-phase smaller than single-phase 100 voltage is higher than 60V, test pencil is bright, test pencil, ground wire is not bright, fire line is bright. The two poles of the neon tube are bright and the alternating current is the direct current. When there are two bulbs at both ends of the manifold, when the DC is measured, the end of the cathode connected to the cathode is bright. Megohmmeter is used to measure large resistance 101 102 CD4001 NAND gate use: 1 can form an RS flip-flop (if there is no 4043): When s is 1, the output 1 s changes back to 0. The output does not change. In this case, r input 1 is required to reset. 2 can constitute a harmonic oscillator with low precision 103 for the audio signal, the initial small, only 5mV, amplified by the preamplifier to 500mV, and finally through the power amplifier output. 104 electron tube is made by the principle of solid heating to release electrons. 105 rough estimate that for a device with an input impedance of 10K, 0.1u can filter out waves above 1000HZ. 10u can filter out waves above 10HZ. 106 for the triode 9013 is used to amplify the input signal voltage for the mv level current uA level output signal voltage about 1V output current mA level Voltage and current amplification factor is about 100. Power amplification is about 10000. 107 low frequency signal refers to the signal from a few Hz to a dozen KHz 108 two capacitors and two diodes can constitute a voltage doubler circuit The 109 oscillating signal is an RF oscillating circuit generated by positive feedback to generate a radio frequency signal. The RC oscillating circuit generates an audio signal. The crystal oscillating circuit generates oscillation by the piezoelectric effect of the crystal. Multivibrator: An oscillator capable of outputting multiple harmonic signals 110 DTL means that the IC is composed of a diode and a triode. The TTL is that the IC consists only of a triode. 111 Process control refers to the control quantity as pressure, liquid level, flow rate, temperature, etc. The object of servo control is position. Compared with ordinary diodes, the 112 Zener diode has a reverse breakdown voltage (stable voltage) of less than 40V and a small change in the reverse dynamic resistance. When the 113 transistor is used for amplification, Rb/Rc is slightly smaller than the current amplification factor β. The base must be connected to a resistor. Otherwise, the input resistance of the transistor is equivalent to 0. When the two diodes are connected, the first Rc should be one tenth of the second Rb, so that the waveform is not deformed. The base can be connected without a resistor. In this case, the first stage must have a pull-up resistor. As a result, the collector output of the previous stage is always 0. When the output of the previous stage is 0, the current flows from the previous stage. When the first level is high, the current flows from behind, and the latter transistor is turned on, but it is not convenient to measure the observed waveform. Therefore, it is recommended to add a resistor to the base, and the resistance is better than the Rc of the previous stage, so that it is convenient to use the oscilloscope. Observation waveform 
Encoder
Optical Rotary Sensor,Custom Encoder,Optical Encoder 6Mm Shaft,Handwheel Pulse Generator
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