Trouble working with LC circuits

[johnboyman]

Hello. I am experimenting with LC Circuits. So far I know that 1/2*Pi *Sqrt(LC) will give you the frequency of the lc cricuit. So when i decide which components to use I can start with that. I was wondering though in a circuit with a 60 hertz supply. What is the minimum and maximum frequencies that i can run in that circuit without it damaging or negatively effecting a transformers performance? If i wanted to raise the frequency above 60 hertz what kind of ways can i use to stop negative feedback? thanks.

 

[berkeman]

Hello. I am experimenting with LC Circuits. So far I know that 1/2*Pi *Sqrt(LC) will give you the frequency of the lc cricuit. So when i decide which components to use I can start with that. I was wondering though in a circuit with a 60 hertz supply. What is the minimum and maximum frequencies that i can run in that circuit without it damaging or negatively effecting a transformers performance? If i wanted to raise the frequency above 60 hertz what kind of ways can i use to stop negative feedback? thanks.

Be careful changing the frequency of the signal you want to put through a "60Hz" transformer. At lower frequencies you will tend to saturate the transformer, and at higher frequencies you will generally experience higher losses and overheating, possibly leading to a fire. Please do not ask me how I know this...

Why don't you just use your signal generator to drive into your LC experimental circuits, rather than going through a coupling transformer?

 

[johnboyman]

I am trying to learn and perfect my formulas.

 

[f95toli]

Why is 60 Hz at all significant? You are presumably not going to connect your circuit directly to an outlet on the wall?
If you are experimenting you should -as Berkeman has already pointed out- use a signal generator.

 

[sophiecentaur]

I was wondering though in a circuit with a 60 hertz supply.

It worries me that you are thinking in terms of using the mains as an initial source of signals. For other frequencies, the mains will be of no use. If you want a cheap audio tone source then why not use your PC and audio card? There are many tone generators available on the Web - and all signals would be at a safe level!

 

[yungman]

Plenty of used signal generator for cheap

https://www.ebay.com/sch/i.html?_fr...erator&_sacat=181939&rt=nc&LH_ItemCondition=4

Don't play with the AC line. If you use ac line 60Hz, you are limited to single frequency. Also, as you lower the frequency, the L and C are going to be much higher values and cost a lot more money. With generator, you go higher frequency and get components really cheap. You might save a portion of money buying the components and use on a generator. Generator can be used in the future, your L and C likely go to waste after the experiment.

If you are getting into electronics, get a decent one, it's important to have a signal generator.

 

[yungman]

I forgot to mention last night, even if everything works out, you cannot sweep frequency with line 60Hz. Sweeping frequency is important to experiment with LC circuits to look at the bandwidth. So if you design the 60Hz resonance circuit, then what? You cannot proof the Q or anything. Hell, you can't even proof you are at the center frequency at 60Hz if you cannot change the frequency to sweep to verify.

The only thing you can proof for a series resonance circuit using line 60Hz is when things start smoking or the circuit breaker pops! Remember is the series res. circuit, it's like an open circuit except at the resonance frequency, then the impedance goes very low depends on the Q, it will put a short circuit on the line( or across the stepdown transformer you use).