| 摘要 |
1488689 Monitoring battery voltage; measuring voltage THOMSON-CSF 26 Nov 1974 [27 Nov 1973] 51258/74 Heading G1U In monitoring battery voltage e.g. while charging, the voltage is applied across two dividers, one providing a fixed fraction of the voltage and the other providing the battery voltage reduced by a fixed amount, these derived are compared and any difference used to illuminate an indicator. One divider comprises two equal resistances Rl, R2 and the other has a Zener diode Z, of threshold voltage equal to half the nominal battery voltage, in series with a third resistor R3 equal to the other two. According to the relative magnitudes of the voltages at A, B, one of diodes D1, D2 conducts and either L1 or L2 is illuminated. If the battery voltage is correct neither conducts. The diodes may be L.E.D.'s, in which case L1, L2 are omitted. In a modification a lamp is connected between A and B which glows when any difference voltage occurs. In a modified circuit Fig. 4 (not shown), a diode bridge is connected between A and B to apply the higher potential to the emitter and the lower potential to the base of a PNP transistor which when conducting illuminates a lamp via a switching transistor. In the Fig. 5 (not shown) embodiment, the diodes of Fig. 1 are replaced by the collectoremitter paths of transistors whose bases are connected to A and B respectively. |
