Determine the positive and negative polarity of SMD diodes, voltage regulators, LEDs through packaging and digital multimeter

Diodes are commonly used electronic devices in electronic circuits, including ordinary diodes, Zener diodes, LEDs, etc.

Judging by the package: Generally, the diode with a horizontal line on one side is the negative pole, and the LED with a horizontal line on the back is the positive pole (T-shaped mark).

I am always confused about judging the positive and negative poles through the package (especially the cross-cut end of the tantalum capacitor is the positive pole). Generally, as an electronics personnel must have a multimeter, it is very simple to judge through a digital multimeter.

Ordinary diode judgment: adjust the gear to K ohms, measure the resistance, and judge according to whether the resistance is large or small. Or use the judgment conduction gear. For a broken diode, the multimeter will make a beeping sound. If it is connected in the forward direction, the multimeter will use a limited number, and the reverse connection will exceed the limit.

LED positive and negative judgment: or use the conduction or resistance judgment, if connected in the forward direction, the LED light will be on, and in the reverse direction, the LED light will not be on.