There are two types of magnetic and piezo buzzers: indicators and transducers. As the piezo element oscillates, the feedback signal will oscillate, and the transistor will alternately block or allow current to flow. A simple way to use feedback is to have the feedback line connected to the base of a transistor. When the main piezo element is actuated, it squeezes the feedback portion, creating a voltage on the feedback line. Feedback is accomplished by dividing the piezo element into two, electrically isolated pieces. Driving circuits for buzzers with feedback tend to be simpler than those circuits without. Some piezo buzzers include a feedback line. Graph showing the relationship between drive signal and audio output in piezo and magnetic buzzers Piezo Buzzer Feedback A piezo buzzer exhibits a reasonably linear relationship between the input drive signal strength and the output audio power while a magnetic buzzer's audio output declines rapidly with a decreasing input drive signal. The frequency of the sound produced by both magnetic and piezo buzzers can be controlled over a wide range by the frequency of the signal driving the buzzer. A piezo buzzer is modeled as a capacitor while a magnetic buzzer is modeled as a coil in series with a resistor. Construction of a typical piezo buzzerĪ piezo buzzer differs from a magnetic buzzer in that it is driven by a voltage rather than a current. This movement of the piezo disk within the buzzer creates sound in a similar manner as the movement of the ferromagnetic disk in a magnetic buzzer or the speaker cone mentioned above. When a voltage is applied across the two electrodes, the piezoelectric material mechanically deforms due to the applied voltage. Piezo buzzers are constructed by placing electrical contacts on the two faces of a disk of piezoelectric material and then supporting the disk at the edges in an enclosure. Piezo buzzers are used in similar applications as magnetic buzzers. Construction of a typical magnetic buzzer The current through the coil is determined by the applied voltage and the impedance of the coil. A magnetic buzzer is a current driven device, but the power source is typically a voltage. The sound from a magnetic buzzer is produced by the movement of the ferromagnetic disk in a similar manner to how the cone in a speaker produces sound. A flexible ferromagnetic disk is attracted to the coil when the current is present and returns to a 'rest' position when the current is not flowing through the coil. In a magnetic buzzer, a current is driven through a coil of wire which produces a magnetic field. However, it should be noted that the greater SPL available from piezo buzzers requires larger footprints. Magnetic buzzers operate at lower voltages and higher currents (1.5~12 V, > 20 mA) compared to piezo buzzers (12~220 V, < 20 mA), while piezo buzzers often have greater maximum sound pressure level (SPL) capability than magnetic buzzers. Many applications use either a magnetic or a piezo buzzer, but the decision regarding which of the two technologies to use is based upon many different constraints. The two most common technologies used in buzzer designs are magnetic and piezo. Understanding some of the technologies and configurations of buzzers is useful during the design process, so in this blog post we will describe typical configurations, provide example buzzer tones, and present common drive circuit options. One of the most common choices for audio communication is a buzzer. As a rule of thumb, if power is supplied by batteries, such as in portable devices, then we recommend piezo buzzers if power is supplied by constant source, such as in PCs or automotive alarms, then we recommend electromagnetic buzzers.There are many choices for communicating information between a product and the user. On the other hand, piezo buzzer feature low input current to a minimum of 1mA to 10mA, higher SPL yet higher driving voltage at least 3V.Ĭlients are advised to decide according to their circuit characteristics, and what type of energy they expect to drive our buzzers. Thus, magnetic buzzer features low input voltage to a minimum of 1.5V, smaller size yet higher consumption current ranging from 40mA to 150mA. Its acoustic vibration is produced by piezoelectric force, which increases as voltage increases. On the other hand, piezo buzzer is powered by electrical voltage. Its acoustic vibration is produced by electro-magnetic force, which increases as current increases. Magnetic buzzer is powered by electrical current.

Should I choose magnetic buzzers or piezo buzzers?

Magnetic vs piezo buzzer