Could this circuit be used to automatically tune a circuit to its resonant frequency?
http://electronics-diy.com/electronic_schematic.php?id=45
http://electronics-diy.com/electronic_schematic.php?id=45
Even with the not shown voltage controlled oscillator this circuit only generates switched fixed frequencies in 100khz steps between it's oscillators total range. First you have to say if that is fine enough frequency resolution for what you require? I suspect this circuit was part of the tuning section to generate a LO frequency for a FM broadchast band receiver.Could this circuit be used to automatically tune a circuit to its resonant frequency?
http://electronics-diy.com/electronic_schematic.php?id=45
Measuring the resonant frequency of the LC network would require the use of a sweep generator (oscillator) and a wide frequency range AC voltmeter. When voltage is max or min (depending on series LC or parallel LC) then that is the tanks resonant frequency. Automating such a test apparatus is not simple of cheap. The industry has for instance Spectrum analyzers with tracking generator that can semi-automate such measurements. Do you really require such an automatic system?What I require is a frequency generator which automatically sets itself to the circuit's resonant frequency.
The circuit is an LC tank circuit, so it will resonate at its natural frequency. In this case however, the capacitor has variable capacitance.
I was thinking that a pickup coil might be able to detect oscillations, and send the signal back to some kind of PLL or something... any ideas?
He wants to find a way to cause a hydrogen/oxygen "HHO"/"hydroxy" cell resonate at it's natural frequency.Why do you want to do this?
It'll need to adapt to a wide range of capacitance. The easy way would be to use a moveable ferrite core in the inductor.Yes the frequency will likely have to adapt to a very wide range.
Yes.Wookie at R1 on your schematic is that a potentiometer?
That's because between the wiper and the right side (towards the output of the opamp) is 9k Ohms and between the wiper and the ground side is 1k Ohms. If the sizes of the capacitor and/or the inductor are radically changed, it may require adjustment of both R1 and R2 to make the circuit oscillate properly.Why does it say 90%?
No, not really - the rise time is too slow, and it's not rail-to-rail. However, as it is, it's a simple way for you to determine your cell's resonant frequency. Just connect the output up to an o'scope or frequency counter.Could the output of the op amp be used to switch a fet for increased power to the circuit?
You'd be doing well to keep things inexpensive then.And yes the application is for hydrogren experimentation though I wish not to disclose much for fear of disapproval.
by Duane Benson
by Aaron Carman
by Aaron Carman