Hi everyone,

Thank you for your help in advance.

I have the following schematic of a equaliser and I cannot understand the operation of L101, I know that L stands for inductor but It doesn't have a value. Also from what I am looking it seems to be just cables leading to number 8.

 

That is a tapped inductor, almost certainly a custom-made part. It is the equivalent of five inductors in series. L101 and its capacitors form a variable (in steps) series L-C network.

https://en.wikipedia.org/wiki/LC_circuit#Series_LC_circuit

Without more information about what the device is (audio, video, radar, ?) and the rest of the circuit it is impossible to say exactly what is going on, but it probably is acting as a high-pass or peaking circuit. Photo?

ak

 

Without more information about what the device is (audio, video, radar, ?) and the rest of the circuit it is impossible to say exactly what is going on, but it probably is acting as a high-pass or peaking circuit. Photo?

ak

Equaliser Question: Cannot Identify Symbol

 

Well, you correctly quoted part of my posting, and correctly copied in the title of the thread without correcting the misspelling.

https://en.wiktionary.org/wiki/equalise

Other than that, I don't see what you are getting at. I have either designed and built, or maintained equalizer circuits for audio, video, and radar signals, which is why I offered those three as examples of what his circuit might be a part of. I answered his question about what the symbol is, but to help him "understand the operation of L101" I need to see more of the schematic. Still no response.

ak

 

Hi guys,

Sorry unfortunately because I do not own the schematic I cannot post it. I can tell you that its meant to be an Equalizer. I understood the LC series circuit but shouldn't there be a value on the L? is 101 the value of the L?

Thanks in advance.

 

Hi guys,

Sorry unfortunately because I do not own the schematic I cannot post it. I can tell you that its meant to be an Equalizer. I understood the LC series circuit but shouldn't there be a value on the L? is 101 the value of the L?

Thanks in advance.

No, it is a non-standard device. Something like that is a custom-wound inductor with several "taps" (access points).

 

No, it is a non-standard device. Something like that is a custom-wound inductor with several "taps" (access points).

So how can I approach it? I have the values for the capacitors as it can be seen in the picture and I know the Frequency that enters the SW3 for all 10 positions.

 

So how can I approach it? I have the values for the capacitors as it can be seen in the picture and I know the Frequency that enters the SW3 for all 10 positions.

I guess I am having trouble understanding what you plan to do. Is this a repair? If no, noth8ng happens to inductors - they are rarely (never?) the source of a problem unless a wire breaks from a tap.

Are you trying to build your own from a schematic. If so, you either need to make some calculations and wind your own or buy one from the manufacturer.

Are you just trying to understand the schematic as an academic curiosity? If so, see above and start making some LCR calculations.

 

I am trying to build one from the schematic and I am trying to gather the components.

I have calculated the inductance and I will order an Inductor for each of the tap.

 

Keep in mind that the inductors add up as you move through the taps from left to right. It might be the case that the increments between adjacent taps all are equal.

ak

 

I am trying to build one from the schematic and I am trying to gather the components.

I have calculated the inductance and I will order an Inductor for each of the tap.

Depending on what you plan to do with the circuit, and you did your calculation to find your desired values, pop in some inductors and put a scope on to see how all the filters are working.

You should post back how it's going... I'd be interested myself