Steve Anderson wrote:The 4000 series were the first mass-produced CMOS series that didn't require weird supply voltages like NMOS or PMOS and others that sometimes required negaitve supplies as well (ECL) - horrible. But 4000 soon relised it's shortcomings when interfacing to real logic (even basic 7400 or a slow 1MHz Z80 microprocessor) as being sloth-like, i.e. s.l.o.w...and this varies with supply voltage. It's output drive capability is very limited too.
So along came HC, good for 2-6V, fast, low current consumption which spurred the 78L05 regulators and such (3mA 'do nothing' current). But these have been eclipsed by the likes of the LP2950 series (75uA) and the MCP1702 series (2uA). The 78L05 these days guzzles more current than the real load...if you need battery operation....which is best?
But here, that's probably not our concern. Put simply, the old 4000 series has not much going for it these days, get out of the habit of thinking of 12V, or 9V, unregulated. Regulate, it's so cheap these days.
5V single-supply op-amps are in abundance, admittedly they do have limitations...but watch this space...
The majority of logic families are these days tending towards 3.3V, and 1.8V is closer than the horizon. 5V will be around for some time as evidenced by the 3.3V chips with '5V tolerant inputs'.
Anyway, I'm getting off-topic again...
Steve A.
I do just use regulated power supplies for the projects ,of late i just use a power supply i made its dual regulated 12 and 5 volts there are times where something works best at a specific voltage i then tend to use the Lm317 .
I am glad the new Ic's still can do up to 5 volts i think forgetting what you have would kill a ic or 2 other wise .
No worries i did learn here i do have many old circuit boards scrapped from 70s gear so i may come across those old IC's
BTW going off here as well any one that needs to get an old ic out of a double side soldered PCB heating it off the board i am sure many have found a very hit or miss thing ,and you would be lucky to get out with out braking the ic's leads i found a fool proof way but you need a dremel , the cutting tools like a mini angle grinder.
You have to cut the ic out of the circuit board and leave a little of the board around the ic so you have a little rectangle of board with the ic on it close as you can do ....then you turn it over to the board side cut it right down between the ic leads and the side of the ic same other side ..then whats left is a just a very thin board just with the leads soldered either side ....i then cut the board between each lead whats left is just a tiny square soldered to each lead then its very easy to desolder ......with the bits left you can get ics out with out damage ,its amazing how fast you can do this once you get the knack of it ,its a little bit of work but you get some thing for nothing which other wise would be a waste of time trying .
Back to the project
I am going to try adjusting a 4046 VCO today and see if i can duplicate or better the UJT VCO .
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.