Products Knowledge

What is the 1/2 duty square wave?

If the users are using the piezo electric buzzer with no source or the magnetic buzzer with no source, it is suggested that they should use the 1/2 duty square wave under the condition of incoming voltage and frequency. Why should use this? It is because this condition can help the piezo element inside the buzzer to achieve the highest amplitude. In other words, it is to make the vibration of the piezo element achieve its limitation and thus enable the buzzer to produce the sound output with high energy. It is shown in the following picture :

The definition of the 1/2 duty square wave is that because it is an AC signal, the positive semi-perimeter and the negative semi-perimeter, the upper wave and the lower wave must be symmetric. In other words, either the upper part or the lower part occupies 50%. In the above picture, if the wave of one side escapes and changes into 40%, 30%, 20%, then the AC signal will be more like the DC signal. This will make the noise of the buzzer weaker and weaker. It is shown in the following picture :

The manufacturer can’t provide the users with the above 1/2 duty square wave buzzer because the buzzer itself is an AC signal output by IC. Generally, an IC programmer knows this. If he doesn’t know this, it is suggested that the users should read through the specification manual provided by Hitpoint carefully and this is always on the first page. Forward this to the development staff and change the output wave of the IC program into 50% for both the upper and the lower part. This is the so-called 1/2 duty cycle.