Early Days of the Transistor Radio!

Back in 1954, listening to the radio wherever you went set you back $49.95 (less battery). Marketed as the "world's first pocket radio," the Regency TR-1 was also the first transistor radio. It was jointly developed by Industrial Development Engineering Associates and Texas Instruments and consisted of parts built by various parties scattered throughout the U.S.

Electric Current

How is Electric Current Made?How do Conductors Differ From Insulators?

What Affects Current Flow?

Six Vocabulary Terms:

Electric CurrentAMPERE (AMPS)Electric CircuitConductorInsulatorVoltage Resistance

ELECTRIC CURRENT is the continuous flow of electric charges

through a material.

The unit we use to measure current is called the AMP.

An ELECTRIC CIRCUIT is a complete unbroken path that electric charges flow through. A closed, unbroken circuit allows electric charges to flow. An open, broken circuit does not let charges flow.

A CONDUCTOR is a material that allows electric current to readily flow through it. Metals are the most common conductors.

The atoms of conductors have loosely bound electrons that can move freely!

INSULATORS are materials that do not allow electric charges to flow through

them.

Plastic and rubber make the best insulators.

Cloth and paper insulation used to be used in most home wiring. This was

called “nob and tube wiring” and is now considered dangerous!

Current flow is affected by the energy of the charges and the properties of the objects that the charges flow through.

VOLTAGE or electromotive force can be described as the difference in the amount of possible electric charge between two

points, or the electric potential.

RESISTANCE is the measure of how difficult it is for charges to flow through

an object.

As you know, four factors determine the resistance of an object:

*Diameter *Length*Material * Temperature

As the Length and Temperature of a conductor increase, the resistance of the circuit increases. As the

Diameter of a wire increases, the resistance decreases. Different types of (Materials) conductors

have different resistances.

Ask Mr. Van Etten to play this link!“Colored Heroes, Valley Forge Maps and a Transistor Radio. (start @ 28:40)

http://www.pbs.org/opb/historydetectives/investigation/first-transistor-radio/