wquiles
Flashaholic
In this post Andrew posted a circuit to give a soft start to an incandecent bulb, and I decided to try it out today.
Here is the modified schematic from Andrew that I implemented:
my very mesy bench:
my test circuit OFF:
my test circuit ON:
In these two following shots, the top trace (channel 1) is the voltage at the ON side of the switch, while the bottom trace (channel 2) is the voltage accross the capacitor C1. The vertical scale is 2V/div and the horizontal scale is 100mS/div. Trigger is set off channel 1 on the upward pulse of 1.0V.
Digital Storage Scope of a single, short pulse on the switch. You can actually see the drop in the battery pack's voltage when the FET finally turns ON - see the short dip, before the battery pack recovers, about 150mS after the trigger point:
and two, back to back short pulses:
- battery source: modamag 4xAA series adapter with freshly charged CBP1650 cells
- lamp: standard 3xcell M*g bulb
- R3 = 5K
- R4 = 200K
- C1 = 33uF (100V since it was all I had!)
- 3A, 100V rated N.O. switch
- N-channel FET: International Rectifier IRL3713PBF (super low Rds(on) at 4.5Vgs of 3.3 miliOhms !!!)
Per the scope, the soft start is more or less about 150mS, which to the human eye is VERY fast
I eventually want to build this circuit for powering 3x17670 (protected) cells for a SF MN60 or MN61 bulb on a custom adapter for my M6, so this early sucess with the circuit is a good start. Adapter would look something like this, with the circuit in that open space - of course the rods would be flush with the bottom plate and I would create a new positive end on the top plate:
Thanks Andrew and js for your advice/help so far :bow:
Will
Here is the modified schematic from Andrew that I implemented:
my very mesy bench:
my test circuit OFF:
my test circuit ON:
In these two following shots, the top trace (channel 1) is the voltage at the ON side of the switch, while the bottom trace (channel 2) is the voltage accross the capacitor C1. The vertical scale is 2V/div and the horizontal scale is 100mS/div. Trigger is set off channel 1 on the upward pulse of 1.0V.
Digital Storage Scope of a single, short pulse on the switch. You can actually see the drop in the battery pack's voltage when the FET finally turns ON - see the short dip, before the battery pack recovers, about 150mS after the trigger point:
and two, back to back short pulses:
- battery source: modamag 4xAA series adapter with freshly charged CBP1650 cells
- lamp: standard 3xcell M*g bulb
- R3 = 5K
- R4 = 200K
- C1 = 33uF (100V since it was all I had!)
- 3A, 100V rated N.O. switch
- N-channel FET: International Rectifier IRL3713PBF (super low Rds(on) at 4.5Vgs of 3.3 miliOhms !!!)
Per the scope, the soft start is more or less about 150mS, which to the human eye is VERY fast
I eventually want to build this circuit for powering 3x17670 (protected) cells for a SF MN60 or MN61 bulb on a custom adapter for my M6, so this early sucess with the circuit is a good start. Adapter would look something like this, with the circuit in that open space - of course the rods would be flush with the bottom plate and I would create a new positive end on the top plate:
Thanks Andrew and js for your advice/help so far :bow:
Will
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