I have seen test voltage and assume this is either the max potential between terminals of the choke. Is this correct?
It depends. The DC test voltage is the maximum DC potential between the winding of the choke and the core. Most chokes have relatively low winding resistance, usually on the order of 50-200 ohms. It wouldn't take much DC between the terminals of the choke to exceed the current rating, per Ohm's law.
If you exceed the DC test voltage, it may cause a breakdown of the insulation between the winding and the core.
The maximum AC test voltage would be the voltage between the terminals of the choke. Exceeding the AC test voltage could cause a breakdown of the insulation between layers of the winding of the choke.
Also, I have heard people refer to different types of chokes:
Smoothing
Swinging
Power
etc.
Are these simply referring to their application? Or are these different types of chokes constructed differently other than the specs I noted above?
A smoothing choke is primarily designed to smooth out the a.c. ripple that may be superimposed on the DC output from the power supply. It usually has a fairly wide gap in the core to minimise saturation of the core by the DC flowing through the choke winding.
A swinging choke is used to maintain regulation of the power supply output voltage from full load to about 10% of full load. To maintain "critical" inductance and make the power supply filter network act like choke input instead of capacity input, a large amount of inductance is required at light loads, but at full load, usually about 20% as much inductance is required. To keep the choke a reasonable size, advantage is taken of the saturation characteristic of the core. A much small gap is used in the core than with a smoothing choke. At low current, the inductance is much higher, due to the smaller gap. But at higher current the inductance is drastically reduced due to the saturation effect of the DC. At high current less inductance is needed to maintain the critical value, so a physically smaller choke can be used. The inductance may "swing" from 8 Henries or so at maximum current, to about 40 Henries at idling current. Another very common inductance range for a swinging choke is 5/25 Henries.
I suppose the term "power" choke means it is designed to be used as a filter choke in a power supply as opposed to an "audio" choke which may be used as an audio reactor. One example of audio choke is the modulation reactor in a plate modulated transmitter. Another kind of choke is the "rf" choke, which is used at radio frequencies. Rf chokes may be air core or powdered iron core and look more like an rf coil than a transformer.
Are there other aspects of choke specs I should be aware of?
With audio chokes, internal capacitance may be a factor since it can affect frequency response.
