Applications
Buzzer (English Buzzer) is an integrated structure of the electronic buzzer, belongs to a kind of electronic components, using DC voltage or AC voltage power supply, widely used in the following areas: the computer industry (motherboard buzzer, chassis buzzer, computer buzzer) printers (control board buzzer), photocopying machines, alarm industry (alarm buzzer, alarm buzzer), electronic industry (alarm buzzer), alarm buzzer, alarm buzzer, alarm buzzer, alarm buzzer, alarm buzzer, alarm buzzer, alarm buzzer, alarm buzzer, alarm buzzer, alarm buzzer, alarm buzzer, alarm buzzer. Alarm buzzer), electronic toys (musical buzzer), agriculture, automotive electronics industry (car buzzer, reverse buzzer, car buzzer, motorcycle buzzer) telephone (environmental buzzer), timer, air conditioning, medical equipment and other electro-acoustic industries. Environmental monitoring.
How to buy
There are many kinds of buzzer specifications, you need to know a few parameters (voltage, current, drive mode, size, connection/fixing mode), of course, more importantly, want to get the sound (sound pressure, frequency).
Operating voltage: Electromagnetic buzzers,[4] from 1.5 to 24V, Piezo from 3V to 220V are feasible, but generally Piezo is recommended to have more than 9V in order to get a larger sound.
Current consumption: Electromagnetic depending on the voltage, from dozens to hundreds of milliamps are available, piezoelectric power saving, a few milliamps can be a normal action, and in the buzzer start, the instantaneous need to consume about three times the current,
Driving mode: two types of buzzer are self-excited, as long as the connection to the direct current (DC) can be sounded, because it has been built in the drive line in the buzzer, the buzzer, the buzzer, the buzzer, the buzzer, the buzzer, the buzzer, the buzzer, the buzzer, the buzzer. Buzzer, because the principle of action of the different electromagnetic buzzer to drive 1/2 square wave, piezoelectric with a square wave, in order to have a better sound output.
Size: the size of the buzzer will affect the volume of the size of the frequency of the high and low, electromagnetic type from the smallest 7mm to the largest 25mm, piezoelectric type from 12mm to 50mm or more large.
Connections: common pin (DIP), wire (Wire), SMD (SMD), piezo large and locking screws.
Sound pressure: Buzzer is often 10cm distance as a test standard, distance doubled, about 6dB attenuation, and vice versa, the distance shortened by a factor of 6dB, electromagnetic buzzer can reach about 85dB / 10cm level, piezoelectricity can be done very loud, common alarms, most of them are made of piezoelectric buzzer.
Precautions
The buzzer can't be used as an ore radio because, inside the buzzer, there is an oscillating circuit, which drives a miniature horn inside to emit a beep sound when the power is turned on. A buzzer is not a mere little horn. Also, there are two types of buzzers. One is the one with an internal oscillator; the other is the one that requires an external oscillator, which is an ordinary miniature horn. For the kind that does not come with an oscillator, it is also unusable because its resistance is usually around 32 ohms, and there are also 8 or 16 ohms. These are low impedance, so they won't work.
If there is no high-resistance headphones, you can also use a power transformer, generally 6V or 12V kind of power transformer, power selection of 3 to 5W or so of that kind, because of that kind of transformer, the primary wire diameter is very thin, the number of turns is also a lot of impedance is also very large. The purpose is to enable the load to obtain a good impedance match, so that the load to obtain the maximum power. The method of use is this: the primary transformer (connected to the 220V winding) to the original to connect the high-resistance headphones in that place; the secondary connected to your ordinary headphones can be.