Types and selection of crystal diodes

Point contact diodes are only suitable for low current rectification due to their small contact points, which prevent them from passing high currents. Additionally, due to their small contact points, the inter electrode capacitance is also very small, making them suitable for high-frequency circuit detection.

Surface contact diodes are the opposite of point contact diodes. Due to their large contact surface, they can pass larger currents, but their inter electrode capacitance is large, so they cannot be used in high-frequency circuits and are mainly used for rectification.

Selection - When choosing a detection diodes, the main consideration is high operating frequency and low reverse current (indicating high detection efficiency). Commonly used point contact diodes include 2AP1-2AP9, 2AP9-2AP10, 2AP11-2AP17, and other models; For low-power rectifier diodes, the main consideration is that the maximum rectified current and maximum operating voltage should meet the circuit requirements. Generally, surface contact models such as 2CP1-2CP6, 2CP10-2CP20, 2CP1A-2CP1H are used.

In amateur conditions, a high-frequency transistor with a damaged PN junction can be used as a detection diode, while a low-frequency transistor with a damaged PN junction can be used as a low current rectifier diode.