- From it's specifications, the 2N222A transistor has a beta value of about 100
- The current applied to the transistor base (555 chip output current) measured at: 1.16mA
- Taking the above, 100*1.16mA = 0.116A
- This calculation is confirmed by the measured of current going through LEDs (via the transistor): 0.1A
- This 0.1A is a quarter of the current needed to fully light the LEDs - measuring the current when driving the LEDs directly from the power supply gave a reading of 0.39A (pretty close to the calculated value of 0.42A)
- The transistor's peak base current is 200mA, so the max emitter current (base current * beta value) should be 200ma*100 = 20A - considerably more than the 0.4A needed.
- It should be possible to get the 0.4A - I just need to figure out how to get more current into the base.
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