This is the SATERN Website of Concord, CA.

Training Aids 2

Electrical circuit basics, History of radio

Here is the 'Training Aids' continuation page, giving detailed explanation of topics mentioned in the previous page.

Hams talk about their 'frequency'. The older Hams have to go more frequently. But frequency of what?

Actually the frequency they refer to is of the vibrating electrical charge in the radio's antenna. And the Ripple
Tank from the previous page gives a visual depiction of what the electromagnetic waves would look like as they
emanate from the antenna.
  Wikipedia gives a fair Historical Account of radio.

Any ham should know about simple electricity, and even the Technician test will have some (relatively easy)
questions about circuits. Lets put together a battery and a resistor, both connected with a pair of wires as
shown in Figure 1.

  If the voltage of the battery is 1.4 volts, what is
the voltage measured between ends of the resistor?
  To adjust your thinking on this, you might recall
"Who is buried in Grant's grave?".

The problems will likely not be this easy. But you can find other (more likely) questions in
the CD that comes with your ARRL textbook. Here is another source for test practice.