1. The rectifier diode in the rectifier circuit changes alternating current into DC.

2. The freewheeling diode in the relay circuit plays a protective role.

3. The LED in the signal circuit plays an indicating role.

4. In the switching circuit, the unidirectional conduction of diode is used for switching.

5. The detection diode plays a detection role in the radio.

6. At the same time, the combination of diode and power supply can also realize the functions of limiting and clamping.

7. In some voltage stabilizing circuits, zener diodes can be used to realize the functions of voltage stabilization and temperature compensation.

The function of triode is as follows:

1, first of all, it can play a switching role in the power supply circuit by using its saturation and cutoff States.

2. In the signal amplification circuit, the large and small signals can be amplified by using the current amplification characteristics of triode.

3. Triode can realize the functions of series adjustment and voltage stabilization in the power supply voltage stabilizing circuit.

4. Responsible for driving some circuits that need small signal control, such as relays and digital tubes.

5. Realize oscillation in the oscillation circuit.

6. In the power amplification circuit, different types of triodes are used to realize complementary power amplification.