For detecting NPN and PNP transistor, capacitor, resistor, diode, triode, N-channel and P-channel MOSFET, IGBT, JFET, triac and battery, etc. For detecting NPN and PNP transistor, capacitor, resistor, diode, triode, N-channel and P-channel MOSFET, IGBT, JFET, triac and battery, resistor and capacitor and other components, etc.