LEAP#297 CD4070 Oscillator
This is a widely-shared circuit of a “square wave generator with CD4070”.
I had a few spare minutes so I thought I’d give it a go. Should be straight-forward, looks like a familiar oscillator circuit based on logic gates.
Well, not so fast. I found this configuration extremely temperamental on a breadboard, and the output is more sinusoid than square. It also made me wonder about the performance of this circuit with buffered and unbuffered versions of the chip.
Ultimately, I came up with three workable variants of this circuit. All interesting, but none worth much for practical purposes as the stability and output characteristics are very poor. But they do work, after a fashion!
As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub
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LEAP#296 Solar Pendulum on a Boldport QSOP Breakout
I had a spare BoldPort QSOP Breakout board and for a while had been pondering some interesting use for it. I think I finally found one … a solar pendulum! I discovered some new and creative solar wobble/flip-flap toys while travelling recently, which started me wondering how they work. Design details are scant, much hidden behind patent walls. The trick appears to be in the switching of capacitor-backed pulses through a coil. What is quite impressive is how well they work with only modest internal lighting and very small photovoltaic cells. The final approach I used was inspired by a Nuts & Volts article As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub
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LEAP#295 Frequency Counter Kit
Not that I really need another frequency counter, but it is interesting to see how this one is constructed.
Julian Ilett has a video on a similar kit and his investigation of the circuit was thorough,
including the discovery that the kits available are deritative from original work by Wolfgang “Wolf” Büscher, DL4YHF
(see Frequency counter with a PIC and minimum hardware).
As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub
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LEAP#294 CD4060 Crystal Oscillator
The CD4060 datasheet describes a crystal oscillator configuration for self-driving the ripple counter.
Using a crystal provides very precise (but fixed) frequency control.
As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub
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