There are many types of ballasts in the electrical industry. To get an answe, the type of ballast must be stated.

Yes, an electrical timer can be used to control the on and off operation of the power to self ballast lamps.

A ballast resistor is an electrical device inserted into a circuit to compensate for changes arising from temperature fluctuations. It helps regulate voltage flowing in an electrical system to avoid overloads or battery damage.

A ballast resistor is an electrical resistor whose resistance varies with the current passing through it, thus maintaining a constant current.

A transformer changes the amperage and / or voltage. It literally "Transforms" electrical energy.

A ballast is like a capacitor. Think of a ballast as a short-term battery. It stores power then releases it as needed. A common example of a ballast is on fluorescent lights.

Initially, a fluorescent light needs a big blast of energy to excite the gas molecules into emitting photons (light). Then it only needs a small amount of energy to keep the gas molecules in an excited state. However, that power has to be of consistent amperage and voltage. The ballast is designed to do that.

The electrical ballast stores energy in the same way that a water ballast stores water for stability. Because the electrical ballast stores far more power than the device it regulates requires, it too provides a kind of electrical stability. That's why you often see a fluorescent light flicker or "lose stability" when the ballast starts to go bad.

A transformer transforms voltage and amperage up or down.

A ballast provides a stabile power supply.