Product Description
| Structural principle of buzzer (a) Introduction of buzzer 1. Function of buzzer: buzzer is an integrated structure of electronic sensor, DC power supply, widely used in audio equipment of electronic products such as computers, printers, copiers, alarms, electronic toys, automotive electronic equipment, telephones, timers, etc. 2. Buzzer type: mainly divided into two types: piezoelectric buzzer and electromagnetic buzzer. III. Circuit graphic symbol of buzzer: The buzzer circuit is indicated by the letter "H" or "Ha" (the old standard uses "FM", "LB", "JD", etc.). Schematic diagram of buzzer (II) Structural principle of buzzer 1. Piezo Buzzer: Piezoelectric buzzer is mainly composed of multivibrator, piezoelectric buzzer, impedance matching and resonance box, shell, etc. Some piezoelectric buzzer boxes are also equipped with light-emitting diodes. Multivibrator is composed of transistors or integrated circuits. When connected (1.5v-15v DC working voltage), the multivibrator starts, outputs 1.5-2.5khz audio signal, and impedance matching pushes the sound of the piezoelectric buzzer. Piezo buzzer is made of lead zirconate titanate and lead magnesium niobate piezoelectric ceramic materials. The ceramic surface is plated with silver electrodes, polarized and aged, and then glued together with brass or stainless steel sheets. 2. Electromagnetic buzzer: It consists of an electromagnetic buzzer oscillator, an electromagnetic coil, a magnet, a diaphragm and a shell. After power is turned on, the current of the oscillator passes through the electromagnetic coil to generate an audio signal, and the electromagnetic coil generates a magnetic field. The electromagnetic coil and the diaphragm are the interaction of magnets, and the sound is vibrated periodically. (III) The buzzer was made (1) Preparation of electromagnet M: Iron bolt 100 is wound with wire for about 6 cm, leaving 5 cm of the wire side lead with transparent tape, so that the coil releases the tape, and then stick it in a box, the electromagnet on the well. (2) Preparation of shrapnel P: Cut the iron can with a width of 2 cm, bend it at a right angle, connect the shrapnel to the electromagnet wire, and then bring the shrapnel close to the wood. (3) Contact with paper clip Q, lift the book clip with tape, lead out the wire, and connect the circuit as shown in the figure. (4) Adjust the distance between M and P (by moving the box), the electromagnet attracts the shrapnel, adjust the distance between the contact and the shrapnel, and they can be heard with the beep after the power is turned on. (IV) Active and passive buzzers and passive buzzers Teach you to distinguish between active buzzers and passive buzzers Now on the market, a small buzzer (only 11mm diameter), light weight, low price, and sturdy structure are widely used in various electrical equipment, electronic products, and single-chip circuits that need to make sounds. From the appearance of the two buzzers in the figure, they look the same, but a closer look shows that there is a slight difference in height between the active buzzer A, which is 9mm high, and the passive buzzer B, which is 8mm high. If the two buzzer pins are facing upward, you can see that there is a green circuit board which is a passive buzzer, and there is no circuit board with vinyl closure which is an active buzzer. Step 1 to determine the active and passive buzzers, you can use the multimeter resistance file RXL test: the buzzer is connected to the "+" pin with the black test pen, and the red test pen touches the other pin back and forth. If it triggers cracking, cracking sound and resistance is only 8Ω (or 16Ω), it is a passive buzzer; if there is continuous sound, and the resistance is hundreds of European, it is an active buzzer. The active buzzer is directly connected to the rated power supply (the new buzzer is indicated on the label) can be continuous sound, not passive and electromagnetic buzzer speakers are the same, and need to take the audio output circuit to sound. |
Product Features
The characteristics of passive buzzers are:
1 Passive buzzers do not have an oscillator inside, so they cannot be made to sound if a DC signal is used. It must be driven by a 2K~5K square wave
2 The sound frequency is controllable, and the "Doremifasolasi" effect can be produced.
3 In some special cases, a control port can be reused with an LED
The characteristics of active buzzers are:
1 Active buzzers have an oscillator inside, so they will sound as soon as the power is turned on
2 Convenient program control, a high or low level of the microcontroller can make it sound, but passive buzzers cannot do this.
The weight of each set is about 6g
I. Module description
2 Working voltage 3.3V
6 There are fixing bolt holes for easy installation
II. Module interface description (3-wire system)
1 VCC external 3.3V
2 GND external GND
31/0 external microcontroller 10 ports
III. Shipping list
1 Passive buzzer module (test passed)
Product Photos
Company Information
