Just a little test for Phoenix software brought by the SLAX iso image

Georges Khaznadar <georges.khaznadar@free.fr>

Making a little oscillator

I made a simple oscillator based on one fourth of quadruple schmidt trigger NAND gate (chip 4093). According to the abacus found at http://www.priory.bromley.sch.uk/students/electronics/pdf/hef4093b.pdf, (last page of the datasheet), the trigger thresholds should be near 2.7 and 3.4 V for VDD = 6 V. The diagrams found on page 5 show that the peak output current at the operating voltage we use is less than what would be allowed in a 10 kW resistor, biased with a voltage of 1 V. So the output of one gate acts rather like a current source than like a voltage source. Therefore, the period should be a little longer than the one we may caculate for a capacitor oscillating between thresholds of 2.7 and 3.4 V, when it is fed by a square signal oscillating between 0 and 6 V.

The realisation

The device was soldered « in the air », that is, without PCB. It is alimented with a serie of four 1.5 V batteries .

Illustration 3 ... in the kitchen Illustration 2 - some tools Illustration 1 - a closeup

Foreseeing the period

The values for the resistor and the capacitor are respectively 10 kW and 100 nF, so the relaxation time (t=RC) is 1000 µs.

When the voltage of the capacitor is driven downwards, the duration is

When the voltage is driven upwards, the duration is

so the period should be longer than 629 µs.

Using the phoenix software

The CD-R burnt with the ISO file phoenix.iso, dowloaded some days ago allowed to boot smoothly a laptop (PC-TEK series GREEN320). Then I logged in as root and launched python.

The little program used is the following:

import phoenix

p=phoenix.phoenix()

l=[]

for i in range(100):

l.append(p.period(0))

The 100 measurements feature the following statistics :

min = 239.8 µs, max = 243.0 µs, average 241.1 µs

Georges Khaznadar

2005-08-31T16:37:45