Seven Segment Displays blinking

[EEVaditya]

Hello,
 
  I have Common Anode Seven Segment displays in combination with 2N2222A Transistor and 74LS47. They are blinking at particular setting for e.g. at 100mA but not at 160mA and above.

  Why is it so? Please guide.
 

[CJay]

Hello,
 
  I have Common Anode Seven Segment displays in combination with 2N2222A Transistor and 74LS47. They are blinking at particular setting for e.g. at 100mA but not at 160mA and above.

  Why is it so? Please guide.

How are you limiting the current?

 I.E. they are trying to draw more than the current limit you've set and your PSU is dropping the voltage below their forward voltage requirement?

[EEVaditya]

  Does the tolerance that is 1% or 5% of resistor for seven segment displays make any difference?

[Kleinstein]

Usually the displays are specified at something like 10 mA per segment. So 100-160 mA is a rather high current. Also the 74ls47 does not provide that much current. How is the current changed  ? - usually it's a resistor per segment - so not much to change, as the 74ls47 like a rather constant supply.

Tolerance of the resistors does not really matter, as the LEDs have tolerances as well.