[Jonathan Thomson] just finished writing up his entry for the 7400 logic contest. It’s a voltage doubler that uses a 74HC14 logic chip. Because this is not at all what the chip was meant for–and he’s a sucker for puns–he’s calling it the Illogical Dickson Doubler.
What he’s got here is basically a charge pump built from a set of diodes and capacitors. On the breadboard you see two chips, one is used as a clock signal generator for the other which is acting as part of the charge pump. We’ve seen a string of hacks that
misuse the protection diodes on the inputs of logic chips. In fact, [Jonathan’s] setup uses the same back power concept that barebones PIC RFID tag did. You may remember in that project the chip was being powered from one of the I/O pins, with the VCC pin not connected to anything.
We’ve embedded a video after the break with shows some voltage measurements, as well as an LED being powered from the doubling circuit.
5 thoughts on “Illogical Voltage Double Uses Logic”
Heathkit Analog Trainer ETS-3600
FALSE! ETW-3600. :P
I was positive that the 74HC14’s relaxation oscillator would show up in this contest.
It’s shown up a few times at least. Mine and another entry used it to clock a charge pump. I used it a second time to make a flickering jack-o-lantern by mixing serial non-harmonic frequencies together.
Bloody Stupid Johnson, CET.
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