OUTPUT DEVICES || Getting signals in and out of electronic systems

Q: How do we get enough current out of a device to drive a motor?

A: A grounded emitter switch:

Q: A possible load?

A: An LED:

A2: A Solenoid:

A Darlington Pair can also be used if you need lots of current, they have a huge current gain (Beta squared):

Joe’s secret trick to get 5 volts effectively:

Transforming low voltage to high voltage, diode chain, op amp, push pull—can source

And sink current.