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SQ-208气相色谱仪有时存在点火难、点火后基线不稳的现象。我们在不改变仪器结构的前提下,将检测器的热丝点火改为脉冲放电点火,效果很好,点火成功率达100%,在相同条件下,基线噪声降低一倍。 1.电路工作原理 (1)3.8V的交流电压经D_1～D_4及C_1整流滤波后由D_5、D_6降压至约1.5V。由T_1、R_1L_1、L_2组成电感三点式振荡器。在接通电源时,电源通过R_1提供基极电流,T_1开始导通,L_2上产生感生电势与电源叠加起来,进一步加大I_b和I_c。当电流增大到一定程度时,T_1的H_F减小,L_2上的感生电势也减小,随之I_b及I_c减小。由于L_1电感储能为1/2I~2L.因而产生一个反向电势,使I_b为零,T_1截止.能量放完时,又重新接通电源。如此循环,形成振荡,电路见图1。
SQ-208 gas chromatograph Sometimes there is ignition is difficult, the baseline instability after ignition phenomenon. We do not change the structure of the premise, the detector’s hot wire ignition to pulse discharge ignition, the effect is very good, the ignition success rate of 100%, under the same conditions, the baseline noise is reduced by one time. 1. Circuit works (1) 3.8V AC voltage by D_1 ~ D_4 and C_1 filtered by the D_5, D_6 step down to about 1.5V. By T_1, R_1L_1, L_2 composed of inductive three-point oscillator. When the power is turned on, the power supply provides base current through R_1, T_1 starts to conduct, the induced potential on L_2 and the power supply are superposed, further increasing I_b and I_c. When the current increases to a certain extent, the H_F of T_1 decreases, and the induced potential of L_2 decreases, with the decrease of I_b and I_c. As L_1 inductor energy storage for 1 / 2I ~ 2L. And thus produce a reverse potential, so that I_b is zero, T_1 end. End of energy release, and re-access the power. This cycle, the formation of oscillation, the circuit shown in Figure 1.