There are two driving methods for piezoelectric ceramics.
The first is self-oscillation drive. The circuit principle is to provide positive feedback through a transistor amplifier to form a piezoelectric crystal oscillator, which makes the piezoelectric ceramic sheet work at the resonant frequency fo to produce sound. At this time, the piezoelectric ceramic sheet has low impedance, and the output volume is controlled by the input current, so it is also called the current drive type.
The second is a separately excited oscillation drive, which uses a square wave (or short wave) oscillator to excite sound. At this time, the piezoelectric ceramic chip generally works at a frequency other than fo, so the impedance is higher, the input current is smaller, and it lives in the voltage drive type. The advantage is that the sound range is wider. The sound is better.
1. High voltage resistance (even if 100V voltage is applied to both ends, it is safe and sound)
2. Not easy to damage
6. Reversible conversion signal