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I'm trying to understand this circuit. It is a drive circuit for an ultrasonic atomiser and comes out of the atomisers datasheet. In particular I don't understand the purpose of the voltage regulator, or what Vcc at 5V is.
The regulator is not shown as connected to anything but the 74132 needs a stable 5V supply for it to work so I guess that's what it's there for. It almost certainly provides 5V to the VCC pin on the 74132.
That makes sense. The atomiser will be fed with 12Vpp then. What would be a good guess for the required current or power of this atomiser? It is 10 ohms so with I=V/R ~ 0.4A. But the the inductor in parallel will set up resonance increasing that to something else?
The voltage could be as high as 24 Vpp due to the inductor action, but it isn't because the driver is current limited. If the frequency is optimal tuned, the inductor + transducer will form a real 10 ohm load.
Because of the base and emitter resistor and limited drive voltage. To achieve 24 Vpp output into 10 ohm, the peak transistor current must be 2.4 A, but considering the maximum TTL output voltage, it hardly can't achieve more than about 1.5 A.
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