A: add a capacitor and proper bias

It can be used as a Sawtooth wave generator

1. by connecting the ujt with proper biasing resistors

A: ANALOGUE IT can be AC or DC it is up to the application involved

An analog signal can be a sine wave, a square wave a sawtooth wave or any other varying waveform

The constant R in the sawtooth wave formula affects the slope of the rising edge of the wave. A higher R value will result in a steeper rising edge, while a lower R value will create a more gradual slope.