Diagram of gear symbols on pointer multimeter

The picture below is a MF47 digital multimeter.

The appearance design of the MF47 digital multimeter is shown in the figure below. It consists of a handle, a meter head, a precision measurement switch, an ohmmeter zero adjustment knob, a DC ammeter socket, a transistor socket, etc.

The top of the digital multimeter control panel is the microampere meter. There is a mechanical zero adjuster in the middle below the meter to adjust the mechanical zero position of the meter stem. As shown in the figure below. There are 6 scale lines on the inner diameter scale below the meter stem, from top to bottom, they are the resistor scale line, the current and voltage scale line, the transistor value scale line, the capacitor scale line, the inductor scale line, and the pulse signal scale line. There is also a rearview mirror on the dial to eliminate parallax.

In the middle of the lower part of the control panel is the measurement switch, which can be selected by turning a knob. The measurement switch dial matches the gauge on the meter head and is printed in three colors: red, green, and black.

The MF47 digital multimeter has a total of 4 DC ammeter sockets. There are positive and negative DC ammeter sockets at the lower left of the control panel. It is customary to plug the red DC ammeter into the positive socket and the black DC ammeter into the negative socket. There are 2500V and 5A special sockets at the lower right of the control panel. When accurately measuring 2500V AC voltage, the positive DC ammeter should be plugged into the 2500V socket. When accurately measuring 5A DC current, the positive DC ammeter should be plugged into the 5A socket.

On the upper right bottom of the control panel is the ohmmeter zero adjustment knob, which is used to calibrate the "0Ω" mark on the ohmmeter scale.

The transistor socket is on the upper left of the control panel. The left side of the socket is marked with "N". When testing an NPN transistor, plug it into this socket. The right side of the socket is marked with "P". When testing a PNP transistor, plug it into this socket, as shown in the figure below.