Transformer T11T 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 T11T 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 T11T is a transformer with a onetoone 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 T11T to a device with a 50 ohm source impedance the output impedance of the T11T 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@...]
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

