Although there are many types with different operating characteristics, the basic diode discussed here is an electronic component that only allows current flow in one direction. Often described as a one-way switch or one-way check valve, diodes have many uses in automotive electronics, and checking their operation can be valuable in diagnostics.
![Multimeter Diode Testing](https://s19534.pcdn.co/wp-content/uploads/2024/03/Tool-Intel-9-Feature1.jpg)