Which type of memory chip is used in SSDs and external flash drives?

Nonvolatile memory chips are used in SSDs (Solid State Drives) and external flash drives because they retain data even when the power is turned off. This characteristic makes them ideal for storage solutions that need to preserve data without a continuous power supply.

In contrast, volatile memory chips, such as those used in RAM (Random Access Memory), require power to maintain the stored information and lose all data when the device is powered down. Dynamic memory chips, which are a type of volatile memory, store each bit of data in a separate capacitor, while static memory chips use flip-flops to store bits and also require continuous power to maintain data. These memory types are not suitable for the function of SSDs or flash drives, as their nature does not allow for persistent storage.

Thus, the key feature of nonvolatile memory chips that allows for data retention without power makes them the correct choice for SSDs and external flash drives.