Arcadia Public Library

Discover how transistors can be used to increase voltage, current, or power of an electronic signal while faithfully reproducing the signal's time variation. See how biasing and load-line analysis play key roles in amplifiers, and help prevent distortion. Learn to design a simple one-transistor audio amplifier that increases the voltage of audio-frequency signals.

Learn how electronic devices "talk" to each other by using flip-flops to send computer "words" one bit at a time, and observe how recipient devices reassemble incoming bits using serial-to-parallel conversions. See how Universal Serial Bus (USB) connections transmit communications between devices, and how the T flip-flop is utilized as a frequency divider in quartz watches.

As you grow familiar with physical properties of electric circuits, become acquainted with the instruments used to measure these quantities: voltmeters, ammeters, ohmmeters, multimeters, and the oscilloscope. See how each of these instruments interacts with a circuit to test circuit behavior or measure quantities that may vary over time.

Observe how circuit designers have formulated a wide array of schemes for converting analog signals to digitally encoded information. See how flash converters, integrating converters, and feedback converters use very different methods to accomplish the same goal, and weigh the situational costs and benefits of each.

Now that the versatility of negative feedback has been demonstrated, adjust the strength of negative feedback in op-amp circuits to build amplifiers with whatever gain you choose. Create an amplifier that sums two or more inputs, see a circuit that converts current to voltage, and explore the design and operation of an op-amp-based light meter.

Understand the math behind two basic rules that allow op-amps to leverage the magic of negative feedback: no current flows into op-amp inputs, and with negative feedback, V+ = V -. See how these rules allow op-amps to tame near-infinite gain in a circuit down to the exact amplification you want.

Define what "feedback" means in electronics, and how it can be used in a circuit. Learn how negative feedback utilizes communication between the output and input of an amplifier, and how operational amplifiers use this phenomenon to create thought-controlled robotic arms, intelligent light bulbs, and optical tracking systems.

What is the difference between electricity and electronics? Begin your study of modern electronics by examining this distinction, and observe how electronics use the basic properties of electric circuits in a more sophisticated way. Witness firsthand how resistance is described with Ohm's law, and learn how to measure electric power.

Flip-flops can be connected together to create counting circuits. Examine the circuitry behind 2-bit, n-bit, and decade counters, then see how the interruption of a light beam can be used in conjunction with such a circuit to keep count of people walking by or products moving along an assembly line.

Put your knowledge to use by building a complete audio amplifier. First, create a two-stage amplifier, then add capacitors to increase the amplification, or gain. Add a power output stage to drive a loudspeaker. Finally, add a volume control. In addition, learn how biasing with diodes can eliminate a subtle form of distortion.