[ASK] Converter DC 9 V to 5 V

[afnindar]

ask converter

Hi,

anybody can help me to convert 9 V DC to 5V ?

 

[IanP]

convert 9v to 3.3v

Take a look at the 7805 vltage regulator ..
It is the easiest way of converting +9V to +5V ..

Rgards,
IanP

 

[afnindar]

i will ask with ">8V", How Much Maximum Voltage allowed?

 

[IanP]

Maximum input voltage for 7805 voltage regulators is 35V ..

Regards,
IanP

 

[afnindar]

i have read the datasheet about LM7805, i curious about the thermal ? cant they blow out cause the thermal ?

 

[IanP]

The 7805, and in general all 78XX voltage regulators, has all sorts of internal protections, including Internal Short-Circuit Current Limiting, Output Transistor Safe-Area Compensation, .. , Internal Thermal-Overload Protection ..
If they are not exposed to higher voltages they are rated for, they will not fail ..

Regards,
IanP

 

[afnindar]

0 Volt is sinyal ground? right?

how about converter from > 9 V DC to 3.0 or 3.3 V DC?

 

[IanP]

0V = GND = Ground ..

To step-down from 9V to 3 or 3.3V you can use fixed voltage regulators (go google), or you can use the very popular adjustable voltage regulator: LM317 .. see picture below ..

Regards,
IanP

 

[afnindar]

R1 and R2 in Ohm or Kilo Ohm or Mega Ohm?

 

[IanP]

In this case the values are in Ohms (Ω) ..

Regards,
IanP

 

[afnindar]

do you know how to calc within LM317 Output Power, Resistor 1 and Resistor 2?

Added after 13 minutes:

i guess :
that the calculate every R2 + 240 regulated up to 3 volt? right?

Added after 6 minutes:

so if i want to output power is 3.3 V so i must change R2 to be value :

assume 1 Volt = 80 Ohm
so 0,1 V = 8 Ohm

3.0 V = 140
3.3 V = 140 + (8*3)
3.3 V = 164 Ohm

CMIIW

 

[IanP]

Take a look at the picture below ..

- 1.25V in this formula represents internal voltage reference ..
- 240Ω is the recommended value for R1 ..
- R2*Iadj is very small and can be removed from the equation ..

Taking into account all of the above, for 3.3V output voltage the value of R2 should be ≈394Ω (the closest choice 390Ω) ..

Regards,
IanP

 

[afnindar]

on that case you show to me. the electricity go through the LM317 and not to save to the capacitor first, your first picture LM317 which are there 2 capacitor polarized and non polarized, so electricity could save to them. which save can i used for my regulator?
if i used your first picture your calculation based on datasheet is not match ?

CMIIW

Added after 27 minutes:

i want to ask about the value of C1? are same with value of C2?

regards

 

[IanP]

C1 can be also 10µF but I would add 100nF ceramic capacitor right next to it ..

As far as the input side is concerned, you can use 100-1000µF electrolytic capacitor and, again, 100nF ceramic ..

The formula from the LM317's data sheet is correct and in both given examples I can't see any incorrect values ..

Regards,
IanP

 

[afnindar]

thanks for attention,

great explanation...

regards