Frequently Asked Questions about Rotary Encoders

In the output circuit using a transistor, the collector serves as the output terminal. When the transistor is in the ON state, an output of less than 0.5 V is produced, but when it is in the OFF state, a signal of more than 10 V is output.
To avoid this state, the collector terminal is usually pulled down externally, configuring the system to be at a Low level in the OFF state.

collector output circuit

Collector Output Level