In the process of repairing the instrument, in addition to checking the voltage, it is also necessary to check the working state of the circuit by checking the operating current of the electric tube.
Checking the current is more troublesome than checking the voltage. It is necessary to disconnect the circuit and then string the current meter. This is a direct measurement method. Indirect measurement can also be used if the circuit is not disconnected. For example, directly measuring the voltage across the cathode resistor divides the voltage drop by the cathode resistance value to obtain an approximate current value. After measuring or calculating the current value, it can be compared with the data in the normal working state of the instrument to judge the fault. For example, the anode DC voltage is normal and there is no anode current. The reason is mostly that there is an open circuit in the anode or cathode circuit, the broken tube of the electron tube, the filament is broken, the contact of the tube is poor, and the fixed bias is more than the cutoff. If the anode current is too small, it means the anode. Or the resistance value of the cathode circuit, the aging of the tube, the bias of the fixed gate is too large, such as the anode current is too much due to the short circuit or variable value of the anode or cathode load resistance, the vacuum of the tube is low, the tube is in contact with the pole or the leakage, the fixed grid The bias voltage is too small or even not, the capacitance of the resistor is blocked, and the cathode capacitance of the self-supplied gate bias circuit is broken down.
Both the direct measurement and the indirect measurement can be used to measure the transistor current. In the indirect measurement, the voltage drop of the emitter is first measured, and then the voltage is divided by the emitter resistance to obtain the emitter current. Since the collector current and the emitter current of the transistor are approximately equal, the emitter current is calculated and the collector current is known. According to the magnitude of the current, the fault can be determined according to the above method.
10K PCS Ready HOT OEM Ozone Generator in Car Air Purifier Mite Anti Virus Filter Sterilizer Disinfecting
Features:
O-zone & Anoin Two Mode --- This advanced air cleaner purifier with Anion and O-zone 2-in1 air sterili-zation mode to fresh air and kill harmful mold decompose smoke, odor and formaldehyde, Keep the air fresh!
Anoin Mode Powerful and Enviroment Friendly --- Releas 8million/cm3 Negtive Ion captures up the airborne particles(PM 2.5), pet odor, smoke, kill harmful mold and other harmful gases. No chemical composition and filter requied. Effectively improving the air quality and Prevent harmful substances inhaled into the lungs.
Car Air Purifier,Car Air Cleaner,Car Air Purifier Ionizer,Best Air Purifier For Car
Jiangmen soundrace electronics and technology co.,ltd. , https://www.soundracegroup.com