Not all isolation transformers are built the same, and hence the effectiveness of filtering noise varies significantly between design and implementations. It is the bandwidth that counts, or the limitation of the isolation transformer that filters the noise outside of the pass-band.
- Efficiency ~95%
- Regulation ~5%
- Common mode rejection ratio (CMRR) >= 120dB
- Differential mode rejection ration (DMRR) 1kHz >= 30dB, 200kHz => 45dB
- Primary – secondary capacitance ~0.006pF
- Peak attenuation ~30dB
A truly balanced isolation transformer will have 120dB of rejection at 100Hz! Less balance isolation (not fully balance on winding) will not work as good and as effective.
Putting the numbers with dB might not look significant since dB is not something we work with every day. Let's convert it to gain and see how much noise and spikes attenuation can it actually get!
Hear the Unheard. Hear the Difference.
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