This circuit may help you evaluate your KNB2. http://www.electronics.50g.com/cpg.htm I used 1.8 megohm fixed for the base resistance. With 5V input, output is about 4V. Varying C1 from 470pf thru .047uf varies the pulse width from approx. 10 uS to 500 uS. 73....Ted....AA5CK