One way you can get an impedance reading quickly is to put a potentiometer in series with the load, feed an AC signal to them, adjust the potentiômeter until it reads the same voltage drop as the load, and then measure the resistance of the potentiometer. It's a tip one of my teachers from the tech course told me and I never forgot it.

@RestoreOldRadios

4 жыл бұрын

A great process/technique for sure. You can also do the same and adjust the AC current for 1/2 of the source as well and read the resistance of the potentiometer. I’ve also used a fixed resistor in series with the load and take the input voltage - output voltage / R = I, then output voltage / I to solve impedance Z. Thanks for watching and sharing your knowledge on the subject. Best, Don

Very cool Don, thank you so much for sharing !!!!

@RestoreOldRadios

4 жыл бұрын

Thanks Ron. I appreciate your feedback. Best, Don

Hi Don. very good and simple system for measuring speakers and transformers impedance. Anyway, you know we had a technical discussion about the frecuency to test speakers impedance. You know we talk about tests at 400 Hz, 440 hz and 1 KHz. To know what a right test frecuency is is a problem I must study before to do my project of a electronic device to measure speakers and earphones and audio transformers impedance. But for what I have seen, you did it right in this video, usin 1 Khz. Maybe there is not much difference between 400 Hz and 1 Khz in results... I am not sure... I will must do my own experiments around this concept when have time. Have a nice day and my best wishes for you. Ketk (Spain)

Interesting Don, I can see people using this as a reference video in the future.

@RestoreOldRadios

4 жыл бұрын

Thanks Carl. One for me too as the days pass by ever so quickly. All the best. Don

Hi Don. Very well explained buddy. Thank you for snaring. Has always Liked,Shared,Added to playlists. All my best.

@RestoreOldRadios

4 жыл бұрын

Thank you Bobby. Best, Don

Would be nice to load all this math into an Excel file. Great video, thanks!

@RestoreOldRadios

4 жыл бұрын

Bob, thanks for your recommendation. Let me see what I can do. Best, Don

Is there a place maybe a website to purchase one of these radios fully restored where I won't get taken advantage of. Thank you for your time.

@RestoreOldRadios

4 жыл бұрын

Sorry for my belated response. Check out: www.radioattic.com/radios.htm and start with the premium sellers. Hope this helps. Best, Don

Are you sure this is correct? The transformer is inductive you neglected the phase angle between the voltage and current. You cannot divide the voltage by the current as they are out of phase. The potentiometer method is a better way of measuring the impedance.

@RestoreOldRadios

Жыл бұрын

Thanks for the heads up. I’m working on a Warwick receiver now and will repeat this process and compare it to other M&Ps when I get to that point in the restoration. Hope you’re doing well. Best, Don

@allthegearnoidea6752

Жыл бұрын

@@RestoreOldRadios Hello Don. Yes all good here thanks, just busy at the moment and not enough time. Hope your well. Anything you need just give me a shout. Regards Chris

Did I just see you use a calculator to divide by 10? LOLOL

@RestoreOldRadios

2 жыл бұрын

At times I find myself dividing by 1. LOL Best, Don