Thanks for your comments.
Checking the specs for the HV5522, the recommended operating voltage is
10.8-13.2. I'm working from part specs and schematics for several clocks
that I own. The MOD-6 runs the HV5522 at 8v, the NixiChron runs at 5v to
the HV5530, and the Spectrum 18, at 5v to the
On 21 Apr 2015, at 20:08, John Rehwinkel wrote:
That's using an op-amp as a comparator. This is generally not a good idea.
Use a comparator instead.
In what way is using an op-amp comparator not using a comparator?
John S
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I think you can get by with 4 control signals to the HV5522, so a quad op-amp
will work as a level-shifter.
That's using an op-amp as a comparator. This is generally not a good idea.
Use a comparator instead.
Using devices outside their datasheet-published range is asking for trouble;
I think you can get by with 4 control signals to the HV5522, so a quad
op-amp will work as a level-shifter. Vcc for the op-amp and the HV5522/5530
can be the desired +12V. The minus input pin of each op-amp is set to 1/2
the logic-swing of the arduino, which probably uses 3.3V signalling. You
This is my first attempt and before I go further, I would really appreciate
critique and comments. This will never be a commercial product, just a
platform for me to keep the mind working as I retire from application
software development after many years. I mostly have the software running
on
Thanks for mentioning the HV5522. I wasn't aware this device existed. Just
be aware that VCC is nominally 12V, so you cant drive the inputs with
TTL-level signals (you need a level-shifter). That shouldn't be a problem
because you only need 4 or 5 signals from the Arduino. Going direct-drive
I think you can get by with 4 control signals to the HV5522, so a quad
op-amp will work as a level-shifter.
That's using an op-amp as a comparator. This is generally not a good idea.
Use a comparator instead.
In what way is using an op-amp comparator not using a comparator?
An op-amp
I had an unpleasant experience about 30 years ago (yeah, before the web
existed and you had to use printed databooks...) with a comparator because I
failed to read the datasheet correctly. I didn't realize it had an open-drain
output, and I nearly went berserk trying to figure out why the
I had an unpleasant experience about 30 years ago (yeah, before the web
existed and you had to use *printed* databooks...) with a comparator
because I failed to read the datasheet correctly. I didn't realize it had
an open-drain output, and I nearly went berserk trying to figure out why
the
The attached data is for the LM339. It's called a comparator, but is it the
best choice?
If I understand the formula correctly, if Vcc is +12v and Vin is +5v, a
good value for Vref is around 4v. Using the formula, if Rref is 100 ohms
than R1 should be 200 ohms. Five resistors are needed for
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