A Mystery of Life

[NightFalcon90909]

There are some things in life that just. don't. make. sense.

For example, why do we drive on parkways, but park on driveways?


Something very important that just. doesn't. make. sense. is the fact that most TTL chips and many CMOS chips require 5 volts, when that voltage is impossible to achieve using 1.5 V batteries.

My questions? How do you go about supplying 5.0 Volts to a circuit? Wall outlet + transformer? Specialty battery?

 

[I²R]

4 or more batteries and a voltage regulator. Or fewer batteries and a stepup DC-DC converter.

 

[blueroomelectronics]

Nowadays 5V 1A switchmode wall adapters are cheap. Works great. Else a simple 7805 power supply.

 

[watzmann]

if you know the reason so you'll never think of it as a mystery ,

for example why the week is 7 days ?.......why not 8 or 6 ?

think of it ...... if you thought it's a mystery too tell me and i'll tell you reason

 

[Hero999]

There are some things in life that just. don't. make. sense.

For example, why do we drive on parkways, but park on driveways?

I don't know what driveways or parkways are?

They must be an American thing.

Here in the UK a drive is a short piece of private road connecting one's house and one's garage, is that what a driveway is in the US?

Something very important that just. doesn't. make. sense. is the fact that most TTL chips and many CMOS chips require 5 volts, when that voltage is impossible to achieve using 1.5 V batteries.

You use a low dropout regulator and a 9V battery to give you 5V.

Most CMOS ICs will run from 3V to 15V (some 18V) which will work fine from 3 to 9 AA cells or a 9V battery.

HC CMOS ICs will run from 2V to 6V and will run from a couple of AA cells.

Always take the discharge graph of AA cells into account when using them with your circuits. Assume 1.6V per cell when the batteries are brand new and 1V per cell when they're dead.

My questions? How do you go about supplying 5.0 Volts to a circuit? Wall outlet + transformer? Specialty battery?

You can buy regulated 5V wall adaptors or connect an LM7805 regulator to a 9V adaptor. It's possible to build your own power supply from a 9V 1.5A transformer, a bridge rectifier, a 3,300:mu:F to 10,000:mu:F capacitor and an LM7805 regulator.

 

[gerty]

For small 5 volt power supplies I've used old chargers from broken/obsolete cellphones ..Almost always free.

 

[I²R]

Here in the UK a drive is a short piece of private road connecting one's house and one's garage, is that what a driveway is in the US?

Yes.

A parkway is one sort of toll road here.

 

[Salgat]

CMOS supports voltages as low as around 3V, but that extra volt does help quite a bit, since it allows the circuit to continue running even after the batteries drop in voltage output.

 

[Hank Fletcher]

A 6V battery supply, for instance from four AA batteries, plus a 7805 voltage regulator will supply regulated 5V for longer than if the battery supply was initially 5V. As the 6V battery supply is used, its voltage will drop, but as long as it stays a bit above 5V, the 7805 will continue to supply regulated 5V.

Parkways and driveways? What about hemorrhoids and asteroids? That one always seemed mixed up to me.

 

[audioguru]

Old fashioned TTL uses too much current for a battery. So you need a power supply to heat them up.

Ordinary Cmos works with a supply from 3V to 18V at low current.
High speed Cmos works with a supply from 2V to 6V at low current.

In Canada, I have never seen a toll road.
A parkway is a pleasant drive in a park or beside a river or lake.
My son put some rubber stripes in my driveway.

 

[Hero999]

A 6V battery supply, for instance from four AA batteries, plus a 7805 voltage regulator will supply regulated 5V for longer than if the battery supply was initially 5V. As the 6V battery supply is used, its voltage will drop, but as long as it stays a bit above 5V, the 7805 will continue to supply regulated 5V.

No it won't, depending on the regulator and current draw, the voltage drop will be anything from 1.5V to 3V.

Assuming it's an alkaline, the bettery voltage will quickly drop to about 5V which will be (worst case) 3V after the regulator.

To get any usable battery life, you need to use a low dropout regulator and a 9V battery for TTL.