The varactor detection in the high-frequency circuits
1, positive and negative discrimination that some one end of the varactor is coated with a black marker, this side is negative, while the other end of the cathode. Varactor both ends of the shell and tube were coated with a yellow ring and red ring, red ring at one end to the cathode, and the yellow ring at one end to the negative.
The file can also use the digital multimeter diode, by measuring the varactor diode being reverse voltage drop to determine its positive and negative. Normal varactor diodes, to measure the forward voltage drop, meter reading 0.58 ~ 0.65V; measure the reverse voltage drop readings of the table shows the overflow symbol “1”. Measure the forward voltage drop, the red pen then the cathode of the varactor, the black pen then the negative terminal of the varactor.
2, the performance is good or bad judgment varactor are measured using a multimeter R × 10k file to reverse the resistance value. Normal varactor diode is reverse resistance values are ∞ (infinity). Forward and backward resistance values have a certain resistance or 0 if the measured varactor diode, the diode leakage or breakdown damage.