Hi,
Have been working on a barking dog repellent using a common "dog whistle" circuit with a 555 and boosting the output with a transistor and inductor. However, it does not appear to have enough ooomph to get a 90+ db output at 25-30 KHz. It appears a normal 4 or 8 ohm piezoelectric speaker, drags the output down to an ineffective level.
Thought maybe a high impedance tweeter might do the job but cannot find anything around 200 ohms impedance. Best I could find was "equivalent to 0.3uF" which calculated to only about 21 ohms.
So, does anyone have a circuit that would drive a "regular" 8 ohm tweeter at an adequate output or does anyone know where to obtain a high - maybe 200 ohm, tweeter?
TIA