Electronic Circuits

Audio Circuits

• Audio Amplifier Circuits
• Very Low Noise Amplifier (designed for a phase noise test set)
• Induction Receiver
• White and Pink (1/F) Noise Source
• VLF Whistler Reception See also ELF Monitor with AGC and Hum Removal [Area 50]
• Noisemaking Circuits (police siren and doorbell chime)

Communication Circuits

• Telephone Circuits

Computer Circuits

• 24 Line Parallel Interface for the PC (or just the schematic)
• Serial Port A/D - 12 bits, no power, cheap!

Misc.

• Games - the first game show timer was modified for better performance
• Noisemaking Circuits (police siren and chime)
• Temperature Controlled Ovens
• Christmas Tree (or other plant) Moisture Monitor
• Kitchen Circuits
• Galloping Neons (array of blinking neon lamps)
• Deer Repellent (seismic sensor)
• Shower Stopper
• Gag Circuits: magic lamp, dripper, remote control jammer
• Construction Ideas

Oscillators

• Two-Transistor Atomic Frequency Standard
• Audio Oscillators
• Flip-Flop Flashers, Buzzers, Etc.
• Flasher Ideas (LED flasher, silent metronome, low battery indicator, high voltage generator)
• Tiny Crystal Oscillator High-stability gate oscillator uses two, 5-pin SOT packaged devices.
• Low Distortion Crystal Oscillator

Power Control

• Anti-Flicker Circuit for LED Christmas Lights [Area 50]
• Magic Lamp (Old idea, new twist.)
• Line Powered Flashers (Great for Christmas lights, etc.)
• Stepper Motor Experiment
• Dome Lamp Dimmer
• Emergency Backup Lamp
• Battery Saver (Worth the effort!)
• Windshield Wiper Delay
• Lantern Flasher/Dimmer
• Dimmer/ Motor Speed Control

Power Supplies /Regulators

• Split Supply for Op-Amps
• Mercury Battery Replacement (also see Craig's versions)
• Homemade "B" Battery

High Voltage Circuits

• Battery Chargers
• Power Supplies and Regulators (new low power discrete switcher)
• Cockcroft-Walton Diode Voltage Multipliers
• Battery Discharge Monitor
• Finesse Regulator Noise

Radiation Circuits

• World' Smallest Geiger Counter (Area 50)
• Top of Ion Chambers page
• Cookie Tin Ion Chamber
• Ion Chamber Bias Supply (Battery Topper)
• Cheap but Sensitive Radiation Detector (Even Cheaper and Simpler version)
• Neon Lamp as Resistor
• Nuclear War Detector
• Polonium Pen
• Neon Bulb Quench Experiment
• Geiger Counters

"First Web Page of Radio"

• Crystal Radio and Amplifiers and simple AM transistor radio circuits.(Also see diode detector info.
• Regenerative Receivers
• Reflex Receivers
• The Amazing All-Band Receiver
• Cellular Phone Helper
• Aircraft Receiver
• WWV Converter for the Car
• Rush Converter for the Car
• FM Band Preamplifier
• Antennas Includes longwire, loading coil, active ferrite antenna, active short antenna, vertical.
• FM Band Monaural Transmitter
• Micropower AM band radio station and wireless "phono oscillator"
• Superregenerative Air Band Radio (Area 50)
• FM Radio Microphone with Internal Loop Antenna (Area 50)

RF Circuits

• One Watt Class-C Amplifier
• Two Diode Odd-Order Multiplier
• Diode Frequency Doublers
• unusual Frequency Dividers
• HCMOS Gates Make Frequency Multipliers
• Frequency Tripler Using the CA3028
• Simple Divide-by-N Using '161s
• Waveform Conversion (sine to square and square to sine)

Science

• Test Equipment
• Picoampere Leakage Tester
• Transistor Spot Checker
• V/I Curve Tracer
• Measuring RF Voltages with a VOM
• Synthetic Isolators - great for checking the SWR of antennas, amplifiers, mixers, etc.
• Curious C-Beeper
• Remarkable R-Beeper - by Tom Bruhns

Weather Related Circuits

• Lightning Detectors (also see the readers' versions)
• Barometers
• Rain Detector
• Geiger counters! (weather?) or Ion Chambers
• Cloud Charge Monitor
• Another One-Transistor Cloud Charge Monitor

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