That would be any circuit that does not go off or on by the key.
Certain circuits, yes but not all of them.
What is considered "constant current"
these are essential for circuits which are current sensitive, it regulates the amount of current which serves as protection for circuits. it is commonly used in Laser diode applications.
it keeps constant power to the amp.
No, voltage is not the same in parallel circuits. Voltage is constant across components in a series circuit, but in a parallel circuit, each component has the same voltage as the power source.
series circuits have 1 pathway they have constant current(Amperes) not constant voltage. Resistance=R+R+R+...
12V Constant = Constant power direct from battery. 12V Switched = Accessory power only when turned to the on/accessory position (example: car stereo only turns on when the car is running or in accessory position).
the ACC wire from the stereo is connected to constant power (+12V)
It depends where you live.In most countries, radial circuits are used for both power and lighting circuit.In the UK, ring-main circuits are used for power circuits, while radial circuits are used for lighting circuits.
the term voltage is constant in parallel circuits
Both take current and energy from the power supply and dissipate power.
If it has recently been wired in it has probibly not been wired in correctly. There are normally two power points for a car radio, one constant and another that works only when the ignition is on. By the sounds of it, it is wired into the constant power source, hence not switching off with the ignition.