SN74HC14: 가변저항으로 주파수 변화 안됨

Please show the schematic.

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OSCILLATOR OUT PART

The variable resistor is VR1.

The schematic looks OK.

Please show an oscilloscope trace of pins 1 and 2, with VR1 at different settings.

Both sides were measured. Only the phase shifted, and there was no change in voltage.

Please show the waveform at pin 1.

There is no damage. It operates differently depending on the IC lot.

Just so you know, there are no issues with the previous LOT.

A square wave does not make sense at pin 1. Please double-check that you have measured at the correct pin.

I had an X-ray taken, but it looks different.

Yes, this device underwent a die revision. Can you show pin 1? If you are discharging/recharging the capacitor for oscillation like Clemens said I wouldn't expect to see a square wave at the input to the inverter.

This is exactly what I would expect to see. And in the question, you said that changing the period is what you wanted to achieve; is the problem solved now?

The signal output to the external does not change voltage.

As stated above, while the period changes, there is no variation in the output voltage.

The operation varies depending on the LOT, as shown in the picture above.

These are digital buffers; they always output fixed voltages (near GND and VCC).

Why are you showing a sine wave? What does it have to do with this circuit?