How do you measure DC voltage in multistage FET amplifier?

To measure DC voltage in a multistage FET amplifier, you should first ensure the device is powered on and the input signal is disconnected to avoid interference. Use a digital multimeter (DMM) set to the DC voltage measurement mode. Connect the positive lead of the DMM to the point where you want to measure the voltage (e.g., the drain or gate of a FET) and the negative lead to the common ground of the circuit. This will provide you with the DC voltage level at that specific point in the amplifier circuit.