# Electric OU: These Magic MOSFETS

In which I continue the exploration of Tar Baby’s behaviour, under perturbation. There is a little surprise at the end. No, nobody is gonna jump out atcha….. WARNING: Advanced mathematics ahead!! As a side benefit, I show the calculation of frequency based on the scope’s timebase setting and the cycles PER division count. Since frequency is measured in Hertz (Hz) and 1 Hertz = 1 cycle PER second, written in math notation 1 cycle/second, to find the frequency of a waveform we count the cycles over a known time interval and DIVIDE the cycle count by the time. This gives an answer in … cycles PER second or Hz. If there are 9 full cycles in 10 horizontal divisions, and the horizontal timebase is set to 0.2 milliseconds PER division, what’s the frequency? We solve by dividing. 9 cycles / (0.2 ms x 10) == 9 cycles PER 2 ms == 9 / 0.002 s == 4500 / 1 == 4500 cycles PER second, or 4.5 kiloHertz. It’s quite simple as long as you remember that PER indicates a division operation. And can count past the fingers of one hand, that is. END of ADVANCED MATH WARNING………