DC REGULATED POWER SUPPLY FOR TETRODE/PENTODE VALVE CHARACTERISTICS APPARATUS – GUPTA BRAND 200160 Posted on March 1, 2017May 2, 2017 by admin H.T.1 Voltage/Current : 0-300VDC/30 mA H.T.2 : 0-300VDC/30 mA Bias Voltage/Current : 15VDC to + 15 VDC/10 mA L.T. Voltage/Current : 6.3VAC/1 Amp with 4 round meters.