digital display DC Power Supply HB17...SB: output voltage and current are showed by the LCD screenService occasion:Testing ... , high-middle academy, apparatus, automatic control, electrical equipment, and communication equipment Parameters:Input voltage: AC 220V±10%, 50±5Hz ... CV≤1x10 +2mV, CC≤2x10 +3mA Frequency: 50-60HZ Waveform and noise: CV≤1mVrms, CC≤5mArms Output voltage: regular, uninterrupted, ...