Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

[SOLVED] Basic question about L matching

Status
Not open for further replies.
C

CHL

Member level 3
Joined
Jan 20, 2015
Messages
60
Helped
2
Reputation
4
Reaction score
2
Trophy points
8
Activity points
550
Hello

I'm studying about basic matching circuits and have a doubt.

491px-ATUhowitworks2.svg.png
https://en.wikipedia.org/wiki/Antenna_tuner

As shown above, a matching circuit is used to make 1kohm be 50ohm.

The total impedance is 50ohm and the maximum power will be delivered.

However, voltage or current wave at the 1kohm will not be same with the input.

Although power can be delivered as we want, the voltage or current wave form is different with the input.

Is it fine if only the power is transferred properly?

I think I missed something in this point, but I don't know what it is.

Thanks.
 

Sometimes you want to trade voltage reduction for increased current. Example, public address systems used to be designated 70V. You did not hook the speaker directly to the amplifier. You inserted a step-down transformer for impedance matching. The speaker receives greater current to run on, at reduced voltage. Power is maximized.
 

The voltages and currents will have to be different where the impedances are different.
At the 50 ohm end, there will be much less voltage and much more current than at the 1,000 ohm end.

The increased current comes from a resonant build up of energy in the tuned circuit, which is why this type of circuit needs to be accurately tuned to the operating frequency for highest efficiency.

It will work well, but only over a narrow frequency range.
 

Warpspeed said:
The voltages and currents will have to be different where the impedances are different.
At the 50 ohm end, there will be much less voltage and much more current than at the 1,000 ohm end.

The increased current comes from a resonant build up of energy in the tuned circuit, which is why this type of circuit needs to be accurately tuned to the operating frequency for highest efficiency.

It will work well, but only over a narrow frequency range.
Click to expand...

Thanks for your answer.

However, I'm still don't understand the operation.

Let's assume that the 1kohm load is an antenna.

To transmit the input signal, is it fine to give increased or decreased voltage & current through the matching circuit?

Does the radiation only depend on the power?
 

Radiation depends on the power, and the radiation resistance of the antenna.

The first requirement is to match the antenna impedance to the transmitter.
 
  • Like
Reactions: CHL

    C

    CHL

    Points: 2
    Helpful Answer Positive Rating
Same power but over different impedances..
Do they ( voltage and current) have to be different in your opinion ??
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top