my recent reads..

LEAP#228 Transistor Curve Tracer

This is a fascinating circuit, originally from the IEEE Engineering Sciences & Education Journal Vol 8 No 1 Feb 1999 pp25-26. I’m working from a demonstration by w2aew. It actually builds on the basic StairStepGenerator project and adapts it to perform basic NPN BJT curve tracing - plotting collector currect to collector voltage for different base current values. hero_image It generates curves like this.. curve_2N3904_50kRb As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub


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LEAP#227 KnightRider with a 555 Timer

This is a well-known LED effects circuit using the 555 timer and 4017 decade counter. The 555 timer is configured as an astable multivibrator, with a frequancy of 10.5 Hz at ~50% duty cycle. The clock signal from the 555 drives the 4017 decade counter, providing 10 signal lines. The 10 outputs of the 4017 (Q0 to Q9) are wired to the appropriate LEDs with steering diodes to generate the “Knight-Rider” pattern hero_image As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub


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LEAP#226 Music Box Kit

This is a pretty common kit available from multiple sources, although it appears to have been originally produced by icstation. The heart of the kit is a a potted chip, one of many similar boards primarily produced as the sound effects generators used in toys. the kit adds supporting circuitry on a PCB to drive a piezo speaker and decode 4 switch inputs to select one of 16 effects. As demonstrated here, it is possible to drive the board with a microcontroller. As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub hero_image


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LEAP#225 FQ777-954 Teardown

The FQ777-954 and it’s derivatives has been a pretty hot item in the nano quadcopter category. But good technical information is hard to come by beyond the usual product feature specs. I’m intrigued by the possibilities for building around it, so my first step is to tear one down and collect as much information about the product as I can. hero_image As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub


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