555 ultrasonic wave fish tank oxygen device circuit

Published:2011/5/30 9:23:00 Author:TaoXi | Keyword: 555, ultrasonic wave, fish tank, oxygen device | From:SeekIC

The oxygen device circuit uses the 555 time base circuit as the core, as the figure 15-48 shows. The ultrasonic oscillator is composed of the 555 and R1，R2，C1. If you open the power supply, the circuit will start working, the oscillation frequency fc=1.44/(R1+2R2)C1. The parameters are according to the design of ultrasonic frequency 22.2 kHz. This frequency is three times of the oscillator load HTD's inherent resonance frequency. When the 555 oscillation outputs the low electrical level, the LED has the flashing shine, this means the normal working condition; at the same time it drives the HTD1 and HTD2 to resonate. The HTD1 and HTD2 are two piezoelectric ceramics, HTD is one kind of piezoelectric effect device.



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