[sdiy] Simple voltage controlled clock/counter

[Justin Owen]

Yeah, I purposely left the 555 off the list because I wasn't convinced it would be linear enough - but I should probably check my assumptions on that.

It does tick all the other boxes though so unless there's any other suggestions I might breadboard it up and see.

I would rather avoid the digital option unless there was no other.

Thanks!

J

-----Original Message-----
From: Tom Wiltshire [tom at electricdruid.net]
Received: 10.11.2011 20:54:35
To: Justin Owen
Cc: SDIY List
Subject: Re: [sdiy] Simple voltage controlled clock/counter

The 555 is traditional for that sort of thing. You'll find a million circuits that use it. It's CV *isn't* terribly linear, but it's not bad. How accurate do you need it?

A microprocessor does seem like overkill, but I just finished up using one to replace five flip flops. One chip versus two for the flip flops. That's the world we live in.

Tom

On 10 Nov 2011, at 20:23, Justin Owen wrote:

> Hello,
> 
> I have a need for a 'clock' of sorts - something to drive some counters, clock dividers and some other assorted logic bits'n'bobs.
> 
> It needs to...
> 
> Output a square wave between 0 and 5V-ish
> Voltage controlled and linear - i.e. if 1V = 100Hz then 2V = 200Hz
> Capable of low frequencies - say, approx. 10BPM (0.17Hz) to 300BPM (5 Hz)
> Ideally w/- PWM
> Some sort of sync or reset facility
> 
> Is my best solution to try and get an established VCO schematic down that low/slow?
> Is there a CMOS contender - the 4046 perhaps?
> Is this one of those things that would be better/easier to do in digital?
> ..or something else entirely?
> 
> Thanks in advance,
> 
> Justin
> 
> 
> 
> 
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