I'm looking at this ultrasonic sensor, and it says:
Pin1 is "Power Supply; MUSTa8v-12v requires 8-16VDC regulated with 30mA current capacity
Pin2: Common; Return for DC power supply, TTL outputs and clock signals
Now, how would I regulate a 9v battery to 30mA current? And does Common mean to attach the negative side of the battery to it?