Projects

A brief project description is listed below for currently available PDFs.  You are free to use any of these for your own personal use with the agreement any and all liability for that use is assumed by you.  

NEW PROJECT: AA-10A-1

25 Watt Audio Amplifier

A simple self contained audio amplifier capable of 25 Watts (true rms) output. Line input for mono or stereo program souce and built 

Printed circuit boards for these projects are available from Far Circuits.  The EL-10A -1 boards may be ordered direct under part numbers EL10A121 and EL10A122.  Other projects require artwork which I will send to Far Circuits, CHARGE FREE, for anyone who wants to buy a board.  Far Circuit charges $0.50 per sq. inch for single sided, etched, drilled, solder platted boards including top side legend.

I use Far Circuit boards in my prototypes and they are excellent.  

Mouser Electronics is the preferred supplier for all my projects and other prototyping needs.  While many excellent suppliers exist today, Mouser has consistently met or exceeded my expectations for product availability, pricing and above all service.

AA-10A-1. 25 Watt Audio Amplifier.

A simple self contained audio amplifier capable of 25 Watts (true rms) output. Line input for mono or stereo program source such as computer sound card, audio players or other devices compatible with -10 dBv, 10k Ohm line levels. High impedance microphone input with built-in mic preamp. 

VM-10A-1. True RMS Volt Amp Meter. High quality, low cost instrument that measures true RMS voltage and current using LTC1966 RMS to DC converter chip. Ranges of 0.02 to 200 V(rms) and 0.02 to 100 A(rms). External Current Shunts minimize insertion resistance and allows both RMS and dynamic current measurements.

PS-15D-( ). 13.8 VDC Power Supply. Simple transistorized (no ICs) 13.8 VDC power supplies at 3 to 30 ADC output current with regulation better than 0.1%.

PWB available - use "Contact Us" to request details.

EL-10A-1. Electronic Load.

400 Watt, 40 VDC, 40 ADC, compact Electronic Load for design and testing of power supplies, batteries, solar power systems, DC power distribution systems, rectifiers and more.  Project is complete and ready to download. The two EL-10A-1 printed circuit boards may be purchased from

Far Circuits for $9.80 per set plus $5.50 Priority shipping. 

PS-40A-1. AC Bench Power Supply

AC Bench Power Supply that delivers up to 5 A from 12 to 130 VAC or direct line voltage up to 10 A.  Includes digital voltage and current meters and external monitor points.

MC-20A-1.  Monitor and Control.

Control 13.8 VDC power to your station with this remotely operated control box.  Provides voltage and current monitoring, DC buss on/off switch, fuse, over voltage shut down as well as under voltage disconnect to protect lead-acid batteries from over dis-charge.  Design maximizes battery utilization by reducing distribution losses rather than some techniques that draw the battery down faster and faster as it dis-charges.

PS-15C-2.  Power Supply Float Charger.  13.8 VDC at 0 to 25 ADC continuous duty, not ICAS. Designed to be used with MC-20A-1 for a complete station power system. Will float charge a secondary battery and electronically disconnect for loss of incoming AC power.

PS-30A-1.  Bench Power Supply. 0 to 40 VDC at 0 to 1 ADC voltage and current regulated with very low noise and stable output.  Includes 10 turn potentiometers for voltage and current adjustment. Simple design can be built inexpensively.

PS-90A-1. Micro-current DC/DC Power Supply. Operates from 2.5 to 15 VDC input to provide an isolated DC output that tracks the input.  Can be used to power LCD Digital Panel Meters, obtain reversed polarity voltage or boosted voltage.  Output currents to 2000 uA.  

QRP480. 40 Meter QRP Transceiver.  Originally published in Ham Radio in April 1980.  1 Watt transmitter with a unique harmonic converter receiver that is excellent with no hum, tunable hum or micro-phonics.

RA-20A-1. Remote Ant Sw.

I know I claimed not to duplicate other well written projects, but I designed and built this one out of necessity and was surprised how well it works.