Lichuang EDA learning notes 10 common connector component identification and passive buzzer driving circuit

Common connectors

The connector circuit symbols are indistinct , I'd like to record it .

Jialichuang EDA - left 【 Commonly used libraries 】-【 The connector 】

Component symbols are as follows ：

Components are packaged as follows ：

components and parts 3D Model as follows ：

summary ：

Pin

• HDR-M-2.54_1x2 Single row needle Pin spacing 2.54mm 1*2P
• HDR-M-2.54_2x2 Double row needle Foot distance 2.54mm 2*2P
• HDR-F-2.54_1x20 Single row Row of mother
• HDR-F-2.54_2x2 Double row Row of mother

Wire to wire connector / Terminal block

• CONN-TH_2P-P5.00 Screw type terminal block 2Pin position Foot distance 5mm
• HDR-IDC-2.54-2X3P IDC The connector ( ox horn / Jianniu ) 2.54mm Number of rows :2 2*3P

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Passive buzzer drive circuit

Circuit diagram analysis

• D2 The function of diode is Afterflow effect . The freewheeling diode Ensure that the current is not transient , otherwise , A spike voltage is generated at both ends of the buzzer , The triode may be damaged , And other parts of the whole circuit .
• R8 It is the instantaneous current limiting effect of the signal at the beginning of the triode base
• R7 Is when the single-chip computer IO27 When the pin is suspended , The drop-down , Confirm the level . And there is a certain Anti static effect of . The triode can also be released after being disconnected BE The amount of parasitic capacitance .

Why use 1N4148 Signal diode ？

1N4148 It is a small high-speed switching diode , The switch is fast , It is widely used for unidirectional conduction and isolation of circuits with high signal frequency , Communications 、 Computer board 、 Television circuit and industrial control circuit .

1N4148 The main features ：

• High frequency signal high speed switch , The maximum reverse recovery time is small .
• High reliability glass package .
• High conductivity .
• High frequency small signal

diode 1N4148 and 1N4007 The application difference of

1N4148 It's a switching diode , Withstand pressure 100V, electric current 150mA, Fast reverse recovery , by nS Level .

1N4007 It's an ordinary rectifier diode , Withstand pressure 1000V, electric current 1A , The reverse recovery time is us Level , It can only be used in low frequency circuits .

First , Generally speaking, we use it in freewheeling diode 4148.

Since it is a freewheeling diode , Generally, it is also used for inductive load , for instance ： Buzzer , Relay ;
　　
Several factors to consider are ：

• How fast is the freewheeling diode ？ Just take a suitable value ; such as mS level ,uS level ,nS level ？
• What is the current of freewheeling diode ？ see DS It's a manual , Don't burn it out .
• How high is the voltage of the freewheeling diode ？ see DS It's a manual , Don't puncture .

summary

• 1N4148 ：100V Reverse withstand voltage and 150mA Average forward current , It is very suitable for general rectification in general occasions .4nS The reverse recovery time is sufficient for most applications , Generally in weak current inductive load , Use 1N4148, Such as buzzer and other small current inductive loads ;

• 1N4007： Maximum average forward rectified current ：1A Maximum reverse withstand voltage ：1000V Low reverse leakage current ：5uA（ Maximum ） Forward pressure drop ：1.0V Maximum reverse peak current ：30uA , Reverse recovery time 30us; Generally used in high current load , Such as industrial load （ Relay ）, The power supply is loaded ;

The biggest difference between them is the current , Voltage magnitude , And reaction speed , In a sense ,1N4007 Can replace 1N4148, As long as the reaction speed is not too much ,1N4148 It is destined to be only on the low current influenza load of weak current .

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Reference material

• [1] Buzzer drive circuit diagram analysis ： http://www.ejiguan.cn/2021/changjianwtjd_0406/3251.html
• [2] 【 Little knowledge 】 diode 1N4148 and 1N4007 The difference between ：http://www.trr-jx.com/news_de.aspx?id=99