This simple Linear circuit provides continuously variable regulated current (~25-400mA) from a 4-6 Volt source. I chose a linear design for simplicity, reliability, ease of repair, and to avoid switching EMI in my Cave Radios. The circuit requires only 0.2V headroom above the parallel LED Array voltage to provide regulation at maximum current. The headroom stays low until the LED’s are extinguished at about 0.75V/cell for 4-cell packs.
S:radiolocation.tripod.com
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