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# NE555 Transformers Drop Voltage Output

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#### Fathul Qorib

##### New Member
I made a circuit about ultrasonic generator using NE555 with 28Khz frequency of 110V voltage using step up transformers. But at the time i connect the piezo tranducer the 110V voltage becomes down. What is wrong with my circuit and how to solve it?

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How many Watts does it take to drive your transducer? (Hint: I'll bet that it is >10W)

A 555 used that way (with a 5V supply) is capable of maybe 0.4W?

In real circuit power circuit at 1Amp transformer output 1Amp x 110Volt = 110Watt drives a tranducer with 50Watt if it is a problem on watt logically circuit I am capable of running a tranducer.

I have repaired ultrasonic cleaners that use a piezo transducer that was driven by a push-pull transistor power amplifier that put out 20 to 50W. This is like a single channel audio amplifier that might be part of a powerful car stereo system...

The datasheet for the 555 shows that with a 5V supply and a 100mA load, the output voltage is typically 1.8V peak-to-peak but could be only o.2V if the 555 has minimum spec's.

Why not increase R2 to 1M and get FREE ENERGY out of the transformer.

Is your transformer rated fro 28 KHZ operation and what is the point of having the 120K resistor in series with the primary?

Also just going by rough guesstimates none of your primary LC tank circuit component values look like they would give a resonance frequency anywhere close to 28 KHZ either.

If it was me, at minimum I would be using the 555 to drive a dual power Op amp IC in a H-bridge configuration and be using a proper HF transformer like something salvageable form a common SMPS but rewound to the right turns/impedance matching ratios to make things work.

120K is a pull down resistor the primary transformers are 200ma calculation to get 0.1mA to GND 12V: 0.1mA = 120K, this resistor allows not too much current to run to ground. I am still a beginner in electronics, I am a doctor wanted to make a tool that can help me in doing surgery.

I'm curious as to how a 50W ultasonic transducer would be used in surgery?

If the 120k resistor with a current of only 0.1mA has 12V across it then the primary of the transformer in series with it gets nothing.

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