The advantages of the electromagnetic buzzer are as follows:
1. Because there is no single-sided contact, it has a long service life and high reliability. Can be used continuously for more than 10000 hours.
2. No arc, no radio frequency noise, no interference to others.
3. No large vibration caused by looseness.
4. Accept the mastery of electronic circuits and let them produce all kinds of beautiful sounds, simulated sounds, and intermittent sounds. The tone is pure and not easily whitewashed by noise.
5. Triggered by voltage, so the current consumption is very small, generally less than 20mA, not more than 100mA.
6. small and noisy. The volume can reach 70 dB/20cm and the component thickness is less than 1mm.
7. Extensive operating temperature limits. Working conditions of
electromagnetic buzzer:
1. Ambient air temperature
The upper limit of ambient temperature is 55; The lower limit of ambient temperature is -25;
2. Height
The altitude is usually not more than 2000 meters.
3. Atmospheric conditions
When the ambient temperature is 40, the relative humidity of the atmosphere is less than 50%; it can have a higher relative humidity at a lower temperature; the monthly balance is larger in rainy months, and the relative humidity is 90%, The monthly balance is lower. When the temperature is 25, the surface condensation of the product caused by the temperature change should be considered.
Therefore, when choosing an electromagnetic buzzer, you need to choose the installation aperture, sound form, volume, and whether to have an indicator light according to the specific application, and then choose the connection method according to the actual working situation.
Electromagnetic buzzers are usually powered by DC voltage and are installed in many electronic products. As a sound generating device, the buzzer performs vibration assembly and vibration assembly to sound. Because the buzzer operating current is relatively large, the microcontroller I/O port can not be simply driven. We need to use an amplifier circuit to drive it and use a transistor to amplify the current. Therefore, the electromagnetic buzzer drive circuit is composed of triode, buzzer, freewheeling diode and power filter capacitor.
1. Buzzer: As a sounding element, it can sound when energized. The main parameters are size, detection bias, operating voltage, frequency, current and drive mode. Can be selected according to need.
2. Freewheeling diode: Because the buzzer is an inductive element, the current cannot change instantaneously, so a freewheeling diode is required, otherwise it will damage the drive transistor and interfere with the rest of the circuit.
3. Filter capacitor: This element is used to filter the influence of the current on the other side and increase the AC impedance of the power supply.
4. triode: triode can play the role of switch. The high level of the base can ensure that the triode is turned on and the buzzer is turned on. If the liquid level is low, the buzzer will stop sounding.
In fact, the electromagnetic buzzer has the advantage of both sound and warning, that is, it is a component that can make a similar sound. It is powered by DC voltage and is commonly used in alarm components and reminder components. With alarm function, small size and light weight.
