User manual

Figure 12: NPN transistor circuit symbol

2.7 Diode

A diode lets current through in one direction only and blocks it in the counter-direction. It

can be imagined like a check valve from a water installation.

Conventional diodes are cylindrical like resistors. Their minus pole (cathode) is marked

with a dash.

SMD diodes are very small. They are labelled on top with a short designation consisting

of a letter and a number. The left end of the label marks the cathode (–), the right one the

anode (+).

Figure 13: Diode circuit symbol