To create a linear ramp that repeats over and over, the timing capacitor can be charged by a current source instead of a resistor. This could be a transistor, but there is a convenient current source in a TO-92 package, the LM334. This device will work over a range of 1 to 30 V (its compliance). The current is set by a resistor connected between the set terminal (R) and the output terminal (V-). The current is about 68 mV/R. A 100Ω resistor gives about 0.7 mA. The voltage stated here as 68 mV is
