SU1531012A1 - Voltage indicator - Google Patents

Abstract

The invention is intended for use in voltage control devices. The aim of the invention is to increase the reliability and sensitivity of the indicator. When a control signal is applied to control input 10, transistors 8 and 9 are switched to saturation mode. At the same time, depending on the polarity of the monitored voltage at input 7 of the device, the current will flow either through resistor 3 and LED 1 or through resistor 5 and LED 2. The introduction of resistors 4 and 5 made it possible to separate the base and emitter currents of the transistors while simultaneously controlling different polarities keys, which allowed to reduce the base currents of the transistors 8, 9 and increase the saturation voltage of the transistor 9, thereby expanding the range of controlled negative voltages, and consequently, increase the sensitivity of the indicator and its reliability. 1 il.

Description

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The invention relates to electrical measurements and can be used in voltage control devices.

The purpose of the invention is to increase the reliability and sensitivity of the indicator by extending the range of negative voltages to the region of small values.

The drawing shows a voltage indicator diagram.

The circuit contains LEDs 1 and 2 and resistors 3-6, the mountains 3 are connected between input 7 of the device and the anode of LED 1, the cathode of which is connected to the collector of transistor 8, the emitter of which is connected to the common bus, resistor 5 is on between the device 7 of the LED and the cathode of LED 2, the anode of which is connected to the collector of the transistor 9, the base of which is connected through a resistor 6 to a common length, the control input 10 of the device is connected to the emitter of the transistor 9 and through a resistor A to the base of the transistor 8,

The indicator works as follows.

When a positive polarity control signal is applied to the control input 10 of the indicator, the transistors 8 and 9 go into saturation mode. If the input voltage of the indicator at this time is negative, the magnitude of which is sufficient to shift the light in the forward direction - diode 2 relative to the potential of the collector of the transistor 9, which is

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is equal to the potential of the control input of the device U, then the LED 2 will emit light, indicating a negative polarity of the monitored voltage. Indication current will flow

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from the source of the control signal to the emitter of the transistor 9, and from the collector of the transistor 9 through the series-connected LED 2 and resistor 5 to the input 7 of the device. If the input voltage has a positive sign and its magnitude is sufficient to displace the LED 1 in the forward direction relative to the saturation voltage of the transistor 8, then the LED 1 will emit light indicating a positive polarity of the monitored voltage. The indication current will flow from the monitored source through the resistor 3 and the LED 1 to the collector of transistor 8, and from the emitter of transistor 8 to the common power circuit.

Claims (1)

Invention Formula The voltage indicator, containing two transistors of different conductivity types, the npp transistor collector is connected to the anode of the first LED, whose cathode is connected through a resistor to the device input, the pnpp transistor collector is connected to the cathode of the second LED, which differs By the fact that, in order to improve reliability and sensitivity by expanding the range of negative voltages in the region of small quantities, the second, third, and fourth resistors are introduced into it, the second resistor is connected between the anode of the second LED and the input device, the pnp transistor emitter is connected to the control input of the device, and the base through the third resistor is connected to the bus, the pnp transistor is connected to the total width, and the base through the fourth resistor is connected to the control of the master input devices.