[RogueAngel]

I had an oscilloscope hooked up yesterday to my Cornet. When viewing the output of the heater circuit I noticed I have a 60 HZ ripple.

I am by no means an expert on circuit design, so I have a couple of questions.

1. How much of a ripple voltage is acceptable?

2. What happens if the ripple is "too" much?

3. Given the design of the Cornet, what would be the best way to reduce excessive ripple?

I am using HEXFRED's and computer grade cap's in the rectifier and have a measured the ripple at 2mV and 60 Hz.

Would Schottky's be an improvement?

TIA,
Bobbi

[hagtech]

Yes, there will always be some residual 120Hz ripple.  The filtering makes it a nice clean almost-sinewave with little high frequency content.  Ripple should measure well under 5mV.  That ain't bad considering it started as a 6V signal!   It's over 60dB rejection with just a CRC filter.

Schottkys will perform better than hexfreds, mainly due to the lower voltage drop.  The less voltage dropped in the diodes means you can drop more in the resistor R21.  And that means a higher resistance value leading to a better RC low pass filter.

If you do have hexfreds, you'll have to change R21 to get heater voltage back up to 6.3Vdc.

jh