12-11-2012, 11:59 AM
(This post was last modified: 12-11-2012, 12:04 PM by Radio Fixer.)
I dont know if this adds anything to the discussion but I like to try to prove things for myself ...
Some while ago I did a project that could use half wave or bridge rectification with capacitive filter. I wondered about the de-rating figures for the rectifier configurations, as given by Hammond, and made some measurements.
The transformer was wired, for three configurations, to supply 100V into a resistive load of 480 Ohms (two large mains droppers in series. The configurations were pure AC (RMS), half wave DC and bridge rectified DC (with capacitor input for the rectifier circuits). A Variac was used to adjust the supply voltage to give 100V across the load in each case. A True RMS (TRMS) digital multimeter was used to measure the transformer input current. These compute the TRMS of non-sine waveforms by sampling and digital signal processing.
The results were AC 113mA, HW DC 416mA and FW Bridge DC 189mA.
Interestingly 113 / 416 = 0.27 and 113 / 189 = 0.6 which are close to the Hammond figures.
Gary
Some while ago I did a project that could use half wave or bridge rectification with capacitive filter. I wondered about the de-rating figures for the rectifier configurations, as given by Hammond, and made some measurements.
The transformer was wired, for three configurations, to supply 100V into a resistive load of 480 Ohms (two large mains droppers in series. The configurations were pure AC (RMS), half wave DC and bridge rectified DC (with capacitor input for the rectifier circuits). A Variac was used to adjust the supply voltage to give 100V across the load in each case. A True RMS (TRMS) digital multimeter was used to measure the transformer input current. These compute the TRMS of non-sine waveforms by sampling and digital signal processing.
The results were AC 113mA, HW DC 416mA and FW Bridge DC 189mA.
Interestingly 113 / 416 = 0.27 and 113 / 189 = 0.6 which are close to the Hammond figures.
Gary
