Ultrasonic pet trainer. What's Inside

The AO-100 ultrasonic pet trainer is available for sale. This inexpensive device uses ultrasound to train animals or perhaps repel them. I disassembled this device to see how it works.

An unknown type microcircuit and a D882 transistor were found on the board. The microcircuit may be a logic or microcontroller chip.A 48 kHz signal is sent from the microcircuit to the transistor base. Since the transistor gets hot, I replaced it with a different housing. The zener diode or diode in the glass housing also gets hot during operation.

How to test the operation. The piezoelectric emitter should receive a signal of tens of volts. There's a transformer or choke on the back of the board for this. Apply a drop of water to the emitter, and the water will instantly turn to steam.