Ramp generator

an oscillator that produces a waveform that looks like a ramp. a closely related oscillator is the sawtooth generator.

a ramp generator produces a linearly rising voltage that reaches a maximum. this rise in voltage is called the rise time. when the maximum is reached the voltage falls to zero instantly. this is called the fall time.

the difference between sawtooth and ramp is in the fall times. a sawtooth has a fall time that is not zero.

both types can be free running or triggered. in a free running oscillator the waveform repeats at a frequency determined by the RC time constant. in the triggered type the waveform repeats according to a received pulse called a trigger. triggered oscillators can be very accurate and are used in television and oscilloscopes.

technicality- the fall time for ramp generators is not zero and can never be zero. it can easily be on the order of nanosseconds, a very short time.