Medical ultrasonic nebulizer one

Circuit Working Principle
The medical ultrasonic atomizer circuit consists of a power supply circuit, an ultrasonic oscillator and an atomizer circuit, as shown in Figure 9-110.

The power circuit consists of timer Q, fuse FU, power transformer T, rectifier bridge stack UR, current limiting resistor R2, power indicator LED VL and filter capacitor C4.
The ultrasonic oscillator circuit is composed of transistor V, resistor Rl, potentiometer RP, thermistor RT, capacitors C2, C3 and inductors Ll, ​​L2.
The atomizer circuit is composed of piezoelectric ultrasonic transducer B, capacitor Cl and fan motor M.
When timer Q is turned on, the AC 220V voltage supplies power to M. At the same time, it also provides +5OV working power for the ultrasonic oscillator after T step-down, UR rectification and C4 filtering. The +5OV voltage also lights up VL after being limited by R2.
After the ultrasonic oscillator is powered on, it oscillates and generates an ultrasonic oscillation signal with a frequency of 1.65MHz (B is both the component that determines the frequency of the ultrasonic oscillator and the load of the ultrasonic oscillator). Under the action of ultrasonic waves, high-frequency vibrations are generated (that is, ultrasonic directional pressure drops are generated), and the liquid medicine is sprayed. Cavitation occurs instantly around the sprayed liquid to produce atomization, and then the medicine mist is blown out by a fan.
RP is used to adjust the working current of V, which can be adjusted to about 600mA.
RT is used to stabilize the operating point of the ultrasonic oscillation circuit.
For component selection,
Rl should use a 2W metal film resistor; cell should use a 1/4W metal film resistor or carbon film resistor.
RP uses a 2W small synthetic carbon film potentiometer.
RT uses a 100Ω negative temperature coefficient thermistor.
Cl, C2 and C4 all use CBB capacitors with a withstand voltage of more than 1OOV; C3 uses high-frequency ceramic capacitors or mica capacitors.
VL uses φ5mm high-brightness light-emitting diodes.
UR selects a 1.5A, 100V rectifier bridge stack.
V selects BU406 high back-voltage silicon NPN transistor.
L2 uses a 24μH core inductor; Ll uses φ0.6mm enameled wire and winds 5-10 turns on it.
T selects a power transformer of 35-40W and a secondary voltage of 45-55V.
Q chooses a mechanical timer of 0-60min.
M chooses AC 220V micro fan.
B selects a 1.65MHz finished ultrasonic transducer.