Air Transparency Monitor,
Xenon Flash Receiver - I designed this receiver
circuit many years ago to monitor the quality of a mile long column of air for future optical communications
experiments. The transmitter system (circuit 72 below) uses a powerful xenon flash in conjunction with a
large 12 inch . . . [Circuit by David A. Johnson P.E., 06/17/00]
Air Transparency Monitor-Pg2 - This is Page 2 of the receiver circuit AIR TRANSPARENCY MONITOR, XENON FLASH RECEIVER . .
. [Circuit by Dave Johnson P.E., 06/17/00]
CMOS Schmitt Trigger IC Makes
VCO - By changing the supply voltage fed to a
classic 4584 Schmitt trigger type oscillator, the oscillator frequency can be changed over a range of 50:1.
A 74HCU04 inverter is used at the output of the 4584 to maintain a constant TTL logic level signal . . .
[Circuit by Dave Johnson P.E., 12/01/02]
Light to Frequency
Converter - This circuit uses a CMOS version of
the classic 555 timer, to form a light intensity to frequency converter. A small PIN photo diode is used as
the light detector. The pulses produced are short, so in some applications you may want to stretch them or .
. . [Hobby Circuit designed by Dave Johnson P.E., 05/04/08]