Help, Anyone know what's this transformer?

[Bartronics]

Sorry if this is a dumb question, but does anyone know precisely what kind of transformer this is... indicated  on the schematic and BOM?

I have a project I'm putting together and I've got most of the parts, but I'm not quite sure what this one transformer is?
Is that 8 Ohms and 1 watt? Or is that 8 ohms and 1:1. I'm confused?


Thanks in advance!

[Bartronics]

I keep thinking its something like this? Maybe?

https://www.amazon.com/10pcs-1300-Transformateur-Transformador-Amplification/dp/B0836MJP6J/ref=sr_1_1_sspa?crid=2IN8RRUZ01O2N&keywords=Audio+Transformer%2C+8+ohms&qid=1642809273&sprefix=audio+transformer%2C+8+ohms%2Caps%2C111&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEzVExGWDJYQ0o3VlU4JmVuY3J5cHRlZElkPUEwODM1MDE3MlJJREZIRzVQNTZTViZlbmNyeXB0ZWRBZElkPUEwODI4Nzk1MldXVzREQkczUU44RyZ3aWRnZXROYW1lPXNwX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

[Bud]

8 Ohm to 1000 Ohm impedance transformer.

[Bartronics]

Ok thanks a lot, that makes sense actually... 8/1 K.
The part about it being a matching transformer was throwing me off since there isn't two of them, wasn't sure if that meant matching windings like a 1:1?

[Bud]

Impedance ratio is proportional to turns ratio squared. 1000/8=125 impedance ratio. Square root of 125 is 11.18, we take 11 as integer turns ratio. So you will need 1:11 turn ratio transformer, the winding with less turns connected to 8 Ohm side.

[TimFox]

A "matching" transformer means that the transformer is designed to "match" impedances.  In this case, the 8 ohm side is matched to a 1000 ohm side due to the turns ratio.  The primary and secondary inductances are chosen to work efficiently at these impedances over the audio frequency range.

[Bartronics]

Thanks for the tips and information! Yes I was reading up on matching transformers last night... I found these two links to be quite helpful as well. Matching impedance in audio transformers is an area I need to get a better handle on. Never ending supply of things to learn in electronics.

https://www.electronics-tutorials.ws/transformer/audio-transformer.html

and

http://www.vias.org/crowhurstba/crowhurst_basic_audio_vol1_059.html

[Zero999]

You could use a small mains transformer. 120V primary and 9V, or 12V secondary.