Piet de Pad
Junior Member level 2
Dear reader,
I have a question about using audio transformers as 120Vac 60Hz line voltage sensors.
I know how to measure AC line voltages with dedicated AC voltage transformers like the ZMBT101B or the ZMBT107. To me, these transformers are nice but bulky for the small PCB's that I make. So I thought can I use the 600:600 Audio transformer transformers for this which exist in various sizes. They also exist in SMD formats.
My knowledge of transformer tells me that this should be possible as long the core is not saturated, I'm not so worried about the phase difference between input and output signal. It might be that the pri-sec isolation voltage is an issue.
Below you see some examples of these transformers, The two left are SMD audio transformers. The third from the left is a traditional 600:600 transformer, and the right is an AC voltage sensor. The schematic shows how I want to use it and that is including a series resistor. The transformer seer only 1mA of current.
My question is: does anyone have a good reason why it is better not to do this or better why it is possible but with some points to consider. Let me know in the comments.
Thanks
I have a question about using audio transformers as 120Vac 60Hz line voltage sensors.
I know how to measure AC line voltages with dedicated AC voltage transformers like the ZMBT101B or the ZMBT107. To me, these transformers are nice but bulky for the small PCB's that I make. So I thought can I use the 600:600 Audio transformer transformers for this which exist in various sizes. They also exist in SMD formats.
My knowledge of transformer tells me that this should be possible as long the core is not saturated, I'm not so worried about the phase difference between input and output signal. It might be that the pri-sec isolation voltage is an issue.
Below you see some examples of these transformers, The two left are SMD audio transformers. The third from the left is a traditional 600:600 transformer, and the right is an AC voltage sensor. The schematic shows how I want to use it and that is including a series resistor. The transformer seer only 1mA of current.
My question is: does anyone have a good reason why it is better not to do this or better why it is possible but with some points to consider. Let me know in the comments.
Thanks