When replacing a power supply， what MUST the technician observe？（）
A: voltage
B: current
C: wattage
D: resistance
A: voltage
B: current
C: wattage
D: resistance
举一反三
- The function of direct current regulated power supply is to input an alternating current power of 220volts, so that it can output __________.( ) A: alternating current 200 volts voltage B: direct current 24 volts voltage C: direct current 200 volts voltage D: alternating current 24 volts voltage
- A technician receives a computer for repair and observes that the fan on the power supply is not moving. Which of the following should the technician do？ （） A: Move the power supply voltage switch to 220 volts. B: Add an additional fan to help cool the computer. C: Replace the cable that attaches the power supply to the motherboard. D: Replace the power supply.
- The<br/>common-base amplifier has _()()()__. A: voltage gain, current gain, and power gain B: voltage gain and power gain, but no current gain C: current gain and power gain, but no voltage gain D: current gain and voltage gain, but no power gain
- Two electronic devices are connected in series. When the load device wants to get the maximum ( ), the impedance of that is the same as the output impedance of the source (front-stage) device. A: Current B: Voltage C: Resistance D: Electric power
- Digital multi-meter cannot measure ( ) when the measured circuit is working. A: voltage B: current C: resistance D: None of the above