Electronic Dice - The 555 timer IC is connected for Astable Operation, the clock pulses are fed to the 4017 IC via the 10K resistor. The 4017 is a 10 stage counter, output 6 (pin 5) is connected to RESET (pin 15), thus giving us a 6 stage counter , outputs 0 to 5. 6 of the LEDs are connected as 3 pairs, thus requiring 4 different signals, these signals come from the 4 transistors, which in turn....(added 6/07)

Encoder-Adjustable Display - This circuit has been developed as a semester work for an Electronics class. It features a 7-segment display. The number is set with a quadrature encoder: turning the encoder knob you can adjust the number shown. Building and understanding it you will test your knowledge about interfacing to an encoder, counting, and driving a display to show the information. (electronic design added 6/07)

Experimental 1 kHz Synchronous Demodulator - This circuit employs a synchronous demodulator to separate a 1 KHz signal from noise and measures  the amplitude of the 1 kHz signals once a second at about 60 microvolts per count then sends the measurements via an RS-232 interface for further processing or display. An LED on the board also lights when the measured signal exceeds a preset threshold....(added 6/07)

Fast precision LED driver - The circuit allows a precision regulated drive current to be set to drive an LED, and in response to a TTL level signal, the LED is switched on and off with rise and fall times of less than 500 nanoseconds and less than 7% overshoot. This was designed for biological experiments to study the photo repsonse of cone cells rabbit eyes....(schematic / circuit added 6/07)

Field Strength Indicator-Analog only - (schematic / circuit added 6/07)

Finite State Machine Programmable Logic Controller - Finite State Machine based Programmable Logic Controller.  7 Inputs  8 Outputs  Simple IF/THEN/ELSE based compiler language generates direct EPROM files…. (add 11/05)

Fish Tank Lights & Temperature Sensor  - There are 6 modes in total 4 solid color modes (Blue, Red, Green, White) and 2 "cycle" modes. The cycle modes allow the lights to do a slow transition from one color to the next. (added 10/06)

Flying inductor LED series voltage boost circuit - A circuit that goes in series with a white LED and a 1.5 volt cell to make > 3 Volts to drive a white LED...(schematic / circuit added 6/07)

FM BroADCast Audio Transmitter - (schematic / circuit added 6/07)

FM Transmitter With Crystal Referenced PLL Frequency Control Using LMX1601 ATtiny2313, AT90S2313   - An LMX1601 Phase locked loop, a discreet  FET VCO, and an AVR micro controller combine to make a stable, easy to use monophonic FM transmitter that includes a an audio activated switch that turns the transmitter on only when its being used…(project added 6/07)

Foolproof prototyping chassis - Here's my solution for a prototyping chassis. The H-frame is borrowed from an antique transistor tester chassis. Even the tallest tubes, placed on the middle deck, are within the H-profile, so it can be rolled on any side safely. Instead of drilling all sorts of socket holes on the steel deck, I use disposable top boards made of laminated floor chipboard. ….(electronic schematic added 07/07)

Frequency Meter & Pulse Generator - (circuit schematic added 6/07)

Frequency Meter with 100 MHz RF desktop channel  - This basically the frequency meter section of the frequency meter/pulse generator based on the AT90S2313 described elsewhere on this site, combined with the 100 MHz RF interface described in the page about the RS-232 to 100 MHz RF desktop channel adapter. Built and align this is the same manner as the 100 MHz RF desktop channel adapter.....(electronic design added 6/07)

Frequency Meter with Minimum Mass Wireless Coupler  - A 0 to 2 MHz ferquency meter with a Minimum Mass Wireless Coupler, based on the ATMega8.Range to the Minimum Mass Base Unit is 10 to 15 cm. Since the frequency meter is battery operated, it can be floated from ground, making life in and around the test bench a lot simpler. No need to connect it to the computer or LCD display...(schematic added 6/07)

Frequency meter with wireless Data Channel - This basically the frequency meter section of the frequency meter/pulse generator based on the AT90S2313 described elsewhere on this site, combined with the 100 MHz RF interface described in the page about the RS-232 to 100 MHz RF desktop channel adapter. Built and align this is the same manner as the 100 MHz RF desktop channel adapter....(electronic design added 6/07)

Gainclone for the PC Age - Audio input comes from either the Line-Out of the PC or an external sound card (described later). A small filter consisting of 680Ω/47pF excludes any RF signals from entering the case. 470nF input capacitor should have a high voltage rating since it protects against line voltages being connected to the amplifier, since it is in the signal path it should be a high quality type....(circuit added 07/08/09)  designed by Malcolm Rix