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Transformer T1-1T Output Impedance [1 Attachment]

K5ESS
 

Correction:  The radius isn’t 1.92 it’s the distance between the normalized resistance point 1.0 and normalized resistance of 1.92.

Mike K5ESS

 

From: PHSNA@... [mailto:PHSNA@...]
Sent: Sunday, December 27, 2015 10:11 PM
To: PHSNA@...
Subject: RE: [PHSNA] Transformer T1-1T Output Impedance [1 Attachment]

 

 

[Attachment(s) from K5ESS included below]

Well I’ll take a shot at answering this and welcome any comments/corrections to my reply.  The T1-1T is a transformer with a one-to-one turns ratio, so within limits its output impedance should be equal to that of the source its connected to.  IF it were a perfect transformer which it isn’t.  The Input Return Loss gives a measure of how imperfect it is.  Let’s take the Return Loss figure for 80 Mhz.  and call it 10 dB.  So, if you connect the T1-1T to a device with a 50 ohm source impedance the output impedance of the T1-1T at 80 MHz. will be somewhere between purely resistive impedances of 96.2 and 26 ohms.  To see all the possible impedances presented for the 10 dB return loss you can draw a circle on a Smith Chart centered on 50 ohms normalized to one with a radius of 1.92.  See attached PDF. 

Mike K5ESS

 

From: PHSNA@... [mailto:PHSNA@...]
Sent: Sunday, December 27, 2015 3:18 PM
To: PHSNA@...
Subject: [PHSNA] Transformer T1-1T Output Impedance

 

 

Dear All:

 

Does the Transformer T1:1T has an output impedance of 50 ohm through all the transformer bandwidth?

Does the transformer output impedance change on high frequencies?

 

Bandwidth: 0.08 to 200 Mhz

Branch. Mini Circuits

 

Regards

Alfredo Mendiola Loyola

Lima, Peru