Circuit explanation required

[adnan012]

Hi,

This is 113-kHz transducer mist maker. What is the purpose of using L1, C7 and C8?

h**ps://www.electroschematics.com/ultrasonic-mist-maker/

Best Regards!

 

[BigBoss]

L1 is a High Frequency Choke Coil to prevent the HF Currents to flow to Supply.
C7 and C8 Capacitive Voltage/Current Divider.

 

[adnan012]

Thanks for reply.

There is negative voltage at vout node. What is the reason for it?
The second is LTspice design file. (change extension to .asc)

Regards!

 

[FvM]

There's just an AC voltage with average DC level of zero at output.

Consider that the circuit dimensioning has to be adapted to transducer impedance. I doubt that C8 of 100 nF works with any 113 kHz transducer on the market.

 

[BigBoss]

Thanks for reply.

There is negative voltage at vout node. What is the reason for it?
The second is LTspice design file. (change extension to .asc)

Regards!

Simple, it's A-Class Amplifier. Inductor acts as a Current Source, Coupling Capacitor acts as a Voltage Source.
So, Voltage Swing over Load in A-Class Amplifiers is almost 2xV_dd.
Current Swing is also 2xI_ds(Q)

Note: 10 Ohm Resistor augment the Rise and Fall Time due to C_gsin your simulation
Attention !