Bowden's Hobby Circuits

A small collection of electronic circuits for the hobbyist or student. Site includes 100+ circuit diagrams with text descriptions, several electronic calculators, links to related sites, commercial kits and projects, newsgroups, and educational areas.

Most of the circuits can be built using common components available from Radio Shack, Digikey, Jameco, Mouser, Allied electronics, or salvaged from scrap electronic equipment. Most circuits have been built, tested, and believed to perform as described, however possible mistakes may be found.

What's New Here? (09/15/16)

Semiconductor Data Sheets

TI Semiconductors (search) National Semiconductors (search) Motorola
NTE Datasheet Archive

Java Script Calculators

Resistor Color Code Calculator - Graphical resistor color code calculator by Danny Goodman. Uses pulldown menus and a realistic picture of a resistor.
4,5,and 6 Band Resistor Color Code Calculator - Graphical 4,5 and 6 band resistor color code calculator including tollerance and tempco.
Another Resistor Color Code Calculator - This one uses check boxes instead of pulldown menus and also calculates the equivalent value of two resistors in parallel. My own creation.
Ohm's Law Calculator - Java Script to solve Ohm's Law for Voltage, Current, Resistance and Power. Enter any two unknowns and solve for the other two.
Voltage Divider Calculator - Solves voltage, current, and power dissipation problems for two element resistive voltage dividers.
L or C Reactance Calculator - Java Script to calculate capacitive or inductive reactance and resonant frequency. For ideal devices only, resistance not included.
RC Time Calculator - Java Script to solve R and C values for given values of time or instantaneous voltages.
RL Time Calculator - Java Script to solve R and L values for given values of time or instantaneous current.
555 Timer - Frequency and Time Interval Calculator - Calculates positive and negative time intervals for the 555 timer based on R and C values. Also contains descriptions and operation of each input and output of the timer and schematics for the two basic modes of operation (monostable or "one-shot" and astable or "rectangular wave oscillator"). Also contains a pictorial diagram of the timer connected as a LED flasher and a table of connections for the 556 timer (dual 555 timer).
LED Series Resistor Calculator - Finds the series resistance needed for various series LED combinations and supply voltages.
Several JavaScript Calculators by John Owen. - Audio op-amp filter, Op-amp circuit, Decibels, Zener Diodes and more...
Air Core Inductance Calculator - Calculates number of turns and layers needed for air core inductors.
Gregorian Calendar - Displays any month from Oct 1582 forward.

Links to Other Hobby Electronics Sites and Useful Information

Don Klipstein's LED Website - Lots of useful LED information, FAQs, and sources for the brightest and most efficient LEDs.
Circuit Archive - University of Washington Circuit Archive, lots of good circuits and links.
Tomi Engdahl's Electronic Info - Links to a wide variety of analog and digital circuits.
Imagineering Imagineering On-Line Magazine,The Design Corner, over 100 circuits in pdf format.
Links for FM Transmitter Kits, Circuits, Electronics ...

Tony's Website - Free electronic circuits, R/C Gadgets, and tutorials for the hobbyist. Site in operation since 1995.
Steve Walz's FTP Site - FTP Resource Site, 1000 Files in 50 Directories.
Wenzel and Associates (Circuits) - Technical Library, Hobby Circuits.
Samuel M. Goldwasser Homepage - Silicon Sam's Technology Resource - FAQs, Links, Troubshooting & Repair, Laser info, Circuits.

Deep Cycle Battery Frequently Asked Questions

Wonton Soup Recipe This recipe was copied from a local Chineese take out place. Costs $5 to buy it, and only $2 to make it.

    Electronics Educational Sites

  • Making Electric Circuits And Electronics Projects. Making Electric Circuits And Electronics Projects. Includes theory, circuits, tutorials, and hobby projects.
  • PIC Microcontroller Tutorial This tutorial explains the basic process of writing programs for the PICs and "burning" those programs to the device. A do-it-yourself programmer can be downloaded from David Tait's PIC archiveThe file you need is PIC84V05.ZIP. The file contains DOS software and programmer schematic that will work with PIC16C84, PIC16F84 or the newer PIC16F628, but will not program the full 2K ROM. It's limited to 1K. There is newer PIC programmer software for Win95/98/xP at WinPic that will program the complete 2K ROM (16F628) using Tait's existing hardware.

  • Play Hookey Basic ideas about op-amps, analog circuits, optics, computers and digital logic.
  • Electronics Tutorials A good comprehensive site with detailed examples and book recommendations.
  • The Art of Electronics (Purchase the book) 1125 large format pages, 80 component-selection tables,1500 figures, extensive practical advice, back-of-the-envelope techniques, exhaustive 4000-entry index.
  • LTSpice Version IV LTspice IV is a powerful free analog and mixed signal circuit simulation and schematic capture tool offering unmatched performance, speed and ease of use. LTspice is updated with new features, performance enhancements and device models on a regular basis.
  • DC Circuits Department of Physics, University of Guelph.
  • 555 Timer Circuits - All the electronics info you need to know about the 555 Timer. With over 80 circuits.
  • All About Circuits - Electrical Engineering and Electronics Community.

    Electronic Component Suppliers

  • 4 Star Electronics - Obsolete Electronic Components. Thousands of items, germanium semiconductors, obsolete ICs and memory, relays, switches, connectors, displays, and more.
  • Mouser Electronics
  • DIGI-KEY Corporation
  • Allied Electronics
  • Jameco
  • Radio Shack
  • Electronix Express - Components and test equipment for schools, colleges and industry. Very nice site.
  • Bill's Surplus Parts For Sale- Resistors, capacitors, semiconductors and a few other items. I don't have a large inventory, just more than I need.

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For help with circuits not listed here, please post a message with details to one of the electronic newsgroups, either sci.electronics.basics or Many readers of those groups will offer ideas and a few specifics at no charge.

For help with specific circuits on this site, or some minor modification, please email the details and I will try to resolve it. I can also build completed circuits shown here for a small fee depending on time involved.

Please do not attach large files over 200K to email messages. I still use a dial-up connection with minimal bandwidth, and cannot download large files over 200KB.

Copyright 1996 - 2016 (Bill Bowden)