According to theory the time period for ramp signal generated using the following circuit should be:
\[ \frac{2}{3} \frac{V_{CC}.C_{1}.R_{1}.(R_{1}+R_{2})}{V_{CC}.R_{2}-V_{BE}.(R_{1}+R_{2})} \]
Now... putting the value of Vcc, R1, R2, VBE, RE... the time period comes out to be around 0.9ms.
But...
