An electronic oscillator is an electronic circuit that produces a periodic, oscillating electronic signal, often a sine wave or a square wave.
Elasticity of supply measures how the amount of a good changes when the producer hires more employees. Elasticity of supply measures how the amount of a good changes when the producer uses new materials. Elasticity of demand measures how the amount of a good changes when its price goes up or down. Elasticity of demand measures how the amount of a good changes when its distribution expands.
The cross-price elasticity of demand is used to measure by how much the quantity demanded of a certain good changes as the price of a different good changes. It is defined as the percentage change in quantity demanded of a certain good 1 divided by the percentage change in price of a good 2.