The device can easily measure the transistors, diodes, regulator, SCR and other anti-pressure; capacitor voltage; greater than 10MΩ resistor. Continuously adjustable output voltage, up to 1400V.
Measurement circuit shown in Figure 1 ( Click to download the schematic diagram ). T, 6V transformer rectifier through D5, C3 filtered to provide the regulator Q’s base voltage. Q W can be controlled to adjust the conduction level. A point that control the collector voltage between 4V-1400V change. 500V high-voltage winding output voltage, the C1, D1-D4 double voltage rectifier circuit composed of rectifier, C2 filter output 1400V high voltage. Test, the device under test connected to the A, B between. W resistance transfer of small, Q to the base of potential drop, A point of potential increase. MA until the gauge shows the reverse current rating of the tested tube (measured in the low-power tube <0.1mA, high-power tube <1mA is appropriate.) At this time the voltage is the voltage value table indicates that the reverse current of the back pressure. Measuring high-value resistor, the resistance connected to the A, B, the use of mA divided by the voltage meter reading meter reading, unit: Ω = V / A. Each run, the W to maximum, the output voltage back to a low of 4V.
Q When asked Ic = 1A, β ≥ 5, BVcbo ≥ 1500V, reverse leakage current of <0.01uA. From C1942, C2027, BU208 select high back pressure control, and additional heat sink. T for the tube radio, power transformers, flea market to be purchased.
Voltmeter resistance 10kΩ / V or more. Good to have: 1500V, 500V, 250V, 50V, 10V several files. MA table should be 0.5mA, 5mA two steps. Replaced with a multimeter, respectively. Production to the attention of the insulation between circuits.