-/+ -0.1V Differential Amplifier Circuit using Zero Threshold EPAD MOSFETs :  Circuit Ideas for Designers Application Notes Advanced Linear Devices, Inc.  (app note added 6/06)

1 Transistor FM Receiver:  (circuit / schematic design added 6/06)

1 Valve CW Transmitter:  (electronic circuit added 7/03)

1-transistor FM Transmitter:  A truly minimalist circuit. Performance is relatively poor and stability is a problem. Q1 modulates  signal and acts as an oscillator. L1 and C5 determine  frequency. Decrease C5 for a higher frequency and vice-versa. You won't get a long range transmission with this one.  author claims 50-500 feet. A lot depends on  antenna. It must be made of stiff wire or else  frequency will change as you move  antenna. Experiment with different lengths to get  maximum range. 50cm or less should work reliably most of  time. A longer antenna might give even better range but if you exaggerate,  circuit will begin to oscillate and performance will drop dramatically. A regular telescope whip should work, too.  (added 6/06)

2 Transistor 2 LED Flasher:  (circuit / schematic added 2/06)

2 Transistor Amplifier:  (schematic added 8/03)

2 Transistor Atomic Frequency Standard:  (circuit / schematic design added 6/06)

2 Transistor circuit replaces IC #1:  05/07)/2002  EDN Design Ideas / (added 10/03)    Linear Technology's recently introduced LTC4300 chip buffers I2C clock and data lines to and from a hot-swappable card. This task is difficult because  IC must work bidirectionally, meaning that you can simultaneously and actively drive both sides. However, as is sometimes  case, you can replace a complicated circuit by a simple one without much loss of performance. .

2 Transistor Circuit Replaces IC:  Linear Technology's recently introduced LTC4300 chip buffers I2C clock and data lines to and from a hot-swappable card. This task is difficult because  IC must work bidirectionally (added 8/03)

2 Transistor FM Transmitters #2:  (circuit / schematic design added 6/06)

2 Transistor FM Transmitters:  (schematic added 8/03)

2 Transistor LED Flasher #1:  (schematic added 8/03)

2 Transistor LED Flasher #2:  (schematic added 8/03)

2 Transistors Form Bidirectional Level Translator:  11/07)/96 EDN-Design Ideas / (added 8/03) Planar-magnetic technology is growing in popularity as a design option for dc-dc converters. In addition to providing electrical benefits, planar magnetics offers reduced leakage inductance and improved consistency. It also significantly reduces  cost of magnetics if you integrate it into  printed-circuit board. To use planar magnetics in a dc-dc converter,  switching frequency should be higher than 500 kHz. This high frequency limits  number of turns required for  magnetic element, thus making it easier to implement on  pc board.....

2 Watt Amplifier #1:  (circuit / schematic design added 6/06)

2 Watt Amplifier #2:  Low distortion Amplifier using discrete components (added 6/06)

2 Watt Amplifier #3:  (electronic design added 9/02)

202: Transistor Outline:  National Semiconductor Application Note   (app note added 2/06)

226: Transistor Outline:  National Semiconductor Application Note   (app note added 2/06)

237: Transistor Outline:  National Semiconductor Application Note   (app note added 6/06)

25 Watt MOSFET  Amplifier:  High Quality simple unit. No need for a Preamplifier (added 9/04)

2N2222 40 Meter CW/DSB Tranceiver:  (circuit / schematic design added 6/06)

2-Step Power Conversion: Portable Power for the Future:  Design Solutions 8  Design Notes (Linear Technology)  (app note added 6/06)

2-Transistor Amplifier:  A simple two-stage Amplifier. Use any general-purpose NPN with high gain. It will drive low impedance headphones directly. A speaker will probably require furr boost.  (added 6/06)

2-transistor FM Transmitter:  While re are a plethora of similar 2-transistor schematics available, this one is above average. A major improvement over  little 1-transistor circuit that we've discussed previously, this transmitter consist of two stages.  first transistor is used to amplify audio, which means that  microphone is now much more sensitive to sound.  second one acts as an oscillator.  All in all, this is an interesting project for beginners and more experienced hobbyists alike. Use any stiff wire or telescope whip antenna, just make sure that it's not too long. Range should be about 100m or even more in  open. Stability is still a problem, though.  (added 6/06)

2W Amplifier:   Amplifier operates in Class AB mode;  single 470R preset resistor controls  quiescent current flowing through  BD139/140 complimentary output transistors. Adjustment here, is a trade-off between low distortion and low quiescent current. Typically, under quiescent conditions, standby current may be 15 mA rising to 150 mA with a 50 mV input signal. A simulated frequency response is ... (added 6/06)

3 Transistor Audio Amp (50 Milliwatt ):  Here is a little audio amplifier similar to what you might find in a small transistor radio. (added 6/06)

3 Transistor Audio Amp (50 Milliwatt):  (circuit / schematic design added 6/06)

3 Transistor FM Radio Bug:  (circuit / schematic design added 6/06)

4 Transistor Tracking Transmitter:  (circuit / schematic design added 6/06)

4 Transistor Transmitter:  (circuit / schematic design added 6/06)

4-transistor H-bridge:  an interesting 4-transistor H-bridge variant; this is cheap and easy to build, and best of all is "smokeless" (i.e., no combination of inputs can cause  bridge to self-destruct).   (added 6/06)

500W, Class E 27.12 MHz Amplifier Using A Single Plastic MOSFET:  Application Note Microsemi-formerly Advanced Power Technology APT9903  ( app note added 05/07)

6-transistor H-bridge:  This is  six transistor "Tilden style" H-bridge; while not as old as  original "basic H-bridge," this goes "way back," and is  basis for many BEAM driver circuits (added 6/06)