23mm Piezo Buzzer

23mm Piezo buzzer

Piezo Buzzer circuit schematics

We take a look at the circuit diagram, the buzzer current is still relatively large, so the need to use transistor drive, and added a 100 ohm resistor as a current limiting resistor. Also added a D4 diode, this diode is called freewheeling diode. Our buzzer is an inductive device, when the transistor is turned on to power the buzzer, there is an on-current flowing through the buzzer.

And we know, one of the characteristics of the inductor is the current can not be abrupt, the current is gradually increased conduction, which is no problem, but when off, the "power - transistor - buzzer - to" this loop Truncated, can not pass any current, then the stored current where to go, is through the D4 and the buzzer itself to consume the loop, so as to avoid the reverse current caused by the inductor current shutdown .

Continued turn-off current, which is the name of the freewheeling diode origin.

Buzzers are often used in computers, printers, multimeters these devices make a tone, the tone is generally very simple, that is, simply make a sound on the line, we use the program to do a simple 4KHZ frequency and 1KHZ frequency of sound Procedures, students can study under their own procedures, the actual effect of comparison.