Does anyone have a circuit and code for a simple countdown timer? It needs to count down from 2 hours 30 minutes and display on 3 or 4 7 segment displays.
http://www.btinternet.com/~doug.h.rice/countdown/index.htm
http://www.uoguelph.ca/~antoon/circ/7.2V-Charger.pdf
NiCd Cycler for 7.2 Volt battery packs.
http://www.uoguelph.ca/~antoon/gadgets/c72.htm
Describes a system on 70 cm freqencies to track and locate small rockets.
http://www.tfs.net/~petek/rockets/RDF/70cm.html
with 1K+ output (part1)
http://www.mrs.bt.co.uk/dubus/8902-1.pdf
with 1K+ output (part2)
http://www.mrs.bt.co.uk/dubus/8903-1.pdf
All you need to know about 741 Op-Amps.
http://www.uoguelph.ca/~antoon/gadgets/741/741.html
http://www.mrs.bt.co.uk/dubus/8904-5.pdf
simple sinewave oscillator
http://www.qsl.net/we6w/projects/cpo.jpg
circuit board and circuit for making voltage regulators based on 78xx ICs
http://www.spelektroniikka.fi/kuvat/regu.pdf