Sometimes, there are too many choices in this world. My benchtop function generator can output a sine, square, or saw wave anywhere from 0.01 Hz up to 60 MHz? Way too many choices. At least, that’s what we suspect [Phil Weasel] was thinking when he built this Analog 1 Hz Sinewave Generator.
A KiCad rendering of [Phil]’s design[Phil]’s AWG (which in this case stands for Anything as long as it’s a 1 Hz sine Wave Generator) has another unique feature — it’s built (almost) entirely with op-amps. A lot of op-amps (37, by our count of the initial schematic he posted). His design is similar to a Phased Locked Loop (PLL) and boils down to a triangle wave oscillator. While a 1 Hz triangle wave would absolutely satisfy judges of the One Hertz Challenge, [Phil] had set out to make a sine wave. Using a feedback loop and some shaping/smoothing tricks (and more op-amps), he rounded off the sharp peaks into a nice smooth sine wave.
Sometimes we make things much more complicated than we need to, just to see if we can. This is one of those times. Are there much simpler ways to generate a sine wave? Yes — but not exclusively using op-amps! This entry brings stiff competition to the “Ridiculous” category of the 2025 One Hertz Challenge.
7 thoughts on “2025 One Hertz Challenge: Op-Amp Madness”
I really would like to see a spectrum of the simulation and real sine wave.
Filters at those frequencies are a real challenge, so I totally appreciate this approach.
Always an honor to get featured ….. it started as a “how hard can it be” and quickly spiraled down into madness ….. and in the end it still uses an NE555 as a reference timer XD
I really would like to see a spectrum of the simulation and real sine wave.
Filters at those frequencies are a real challenge, so I totally appreciate this approach.
At the shop:
“bring me all the op amps you have”
“how many???”
“EVERYONE”
Always an honor to get featured ….. it started as a “how hard can it be” and quickly spiraled down into madness ….. and in the end it still uses an NE555 as a reference timer XD
Prints coming next week, wish me luck!
Is it ultra stable or extra low distortion?
If not there are so many simpler ways to make sine wave oscillators with op amps.
“Are there much simpler ways to generate a sine wave? Yes — but not exclusively using op-amps”
Rubbish!
Wouldn’t a Wein Bridge oscillator be a stupidly simple way to make a 1hz oscillator, or am just the stupid one :,)
I would imagine a one up to this would be made from caps, coils, and an op-amp made from tubes. …
Oh wait.