Adding sound to a product can be useful in many cases

Adding sound to a product can be useful in many cases; in addition to checking boxes on product demand lists, a bone-shattering beep is a sure-fire way to alert users to problems in systems.

Murata’s extensive experience in the production of all kinds of ceramic elements put them in the unique position of being able to run other ceramic-based products “just for kicks”. The PKMCS0909E4000-R1 is one example of this – in the bigger hierarchy of things, the product is a square-wave-driven buzzer.

This means that it can not be driven by applying DC. In fact, the datasheet explicitly warns against that due to electro-chemical effects taking place in the substrate. Instead, a figure is provided with the following outline between sound output strength and drive frequency.

The volume reached is dependent on the frequency

As for the actual drive circuit, Murata limits itself to the designs shown in figure two. In principle, a resistor in the range of 1kOhm is suggested to keep the current flowing in the part in check.

Various drive circuits can be used to generate the necessary square wave

Due to the relatively low prices of the component and the ease of the generation of square waves, the product is ideally suited to all situations where multiple different output frequencies are needed. If your system needs only one beep, different components can be slightly easier to handle – but keep in mind that the reduced flexibility may come around to bite you at a later point in time.

Author: Tam Hanna
Published: March 12, 2021