SU1205046A1 - Charging device for metering capacitor - Google Patents

Abstract

The invention relates to a measurement technique and can be used in frequency to voltage converters and analog frequency meters. The purpose of the invention is to expand the functionality by removing the restrictions on the shape and duration of the input pulses and the possibility of their electronic amplitude control. To do this, a voltage limiter 9, a threshold element 10 and a third transistor 12 are additionally introduced in the device. The device also includes a metering capacitor 1, a discharge driver 2, the first and second transistors 3 and 4, the input bus 5, resistors 6 and 7, source 8 power supply, output bus 11. The magnitude of the amplitude of the pulses on the output bus can be set by varying the level of the voltage limiter 9, for example, by setting the zener diodes with a corresponding level of breakdown. When using the voltage limiter shown in the drawing, the amplitude of the output sawtooth pulses can be electrically controlled. 2 Il.

Description

The invention relates to a measuring technique and can be used in frequency converters in voltage and in analog frequency meters.

The purpose of the invention is to expand the functionality by removing restrictions on the shape and duration of the input pulses and the possibility of their electronic amplitude control.

Fig, 1 shows a diagram of the device; Fig, 2-time diagrams,

The device contains a metering capacitor 1, the bit driver 2, the first and second transistors 3 and 4, the input bus 5, the first and second resistors 6 and 7, the source 8 pi

tani, voltage limiter 9, threshold element 10, output bus P and third transistor 42,

The input pin 5 is connected to the base of the first transistor 3 connected according to the common emitter circuit, the collector of which is connected to the output of the threshold element 10 and the base of the second transistor 4 also connected to the common emitter circuit whose collector is connected to the third voltage limiter 9 transistor 12, and through the first resistor with the power source 8, which through the second resistor 7 is connected to the input of the transmissive element 10 and the collector of the third transistor 12, the emitter of which is the output bus 1 1 and connected to the parallel of connected dispensing and discharging capacitor dnym shaper 2,

The device works as follows.

In the absence of input pulses on the input bus 5, the first transistor 3 is locked and the second transistor 4 is saturated with the current of the threshold element 10 flowing from the power source 8 through the second resistor 7, the level of conduction voltage of the threshold element 10 is set lower than the voltage of the power source 8, but a high level of limiting voltage limiter 9.

The saturated second transistor 4 reliably closes the third transistor 12 and the metering capacitor 1 is discharged.

On the leading edge of the input pulse, the first transistor 3N;

0

five

0

thirty

35

25, the second transistor 4 is locked and the third transistor 12 is saturated with a current flowing from the power source 8 through the first resistor 6, which flows into the base of the third transistor 12, and the current through the threshold element 10 becomes zero. This leads to the fact that now the device is indifferently present or there is no pulse on the input bus 5 and in any case it starts the process of charging the metering capacitor 1,. .

The metering capacitor 1 is charged by the emitter current of the third transistor 12, which is the sum of the currents of the first and second resistors 6 and 7, which determine the constant charge of the metering capacitor 1 and the slope of the voltage rise on the output bus 11,

In the process, the charge of the metering capacitor 1 increases the voltage on the emitter of the third transistor 12, the collector of the second transistor 4 and on the voltage limiter 9.

When the voltage on the voltage limiter 9 reaches the voltage limiting level, the voltage at the base of the third transistor 12 stops increasing, the current of the first resistor 6 flows completely into the voltage limiter 9, the base of the third transistor 12 de-energizes and the transistor locks, the voltage its collector rises sharply and, when it reaches the voltage of the onset of conduction of the threshold element 10, the second transistor 4 starts to open with the current of the second resistor 7, as a result of which an avalanche-like process occurs After which the second transistor 4 will be saturated, and the third transistor 12 is locked. The voltage on the metering capacitor I reaches a level approximately equal to that of the voltage drop at the base-emitter junction of transistor 12, if

If the gQ bit driver is not turned on, then the voltage on the capacitor will continue to be maintained until the time of switching on the bit driver 2, for which, for example, the key can be used. If it is automatically turned on at the point in time when the voltage across the collector of the third transistor 12 exceeds the limiting voltage level

After reading voltage 9, a discharge of the metering capacitor 1 will occur and a sawtooth voltage pulse will be generated on the output bus 11, as shown in FIG. 2, the shape of which will be independent of the voltage shape on the input bus 5,

Change the limiting level of the voltage limiter 9, for example, mouth

NON-Zener diodes with an appropriate level of breakdown, set the magnitude of the amplitude of the pulses on the output bus 1, and when using the voltage limiter shown in the drawing, the amplitude of the output sawtooth pulses can be regulated electrically.

Claims (1)

Claim 20 with A metering capacitor charge device containing two parallel-connected metering capacitors and a discharge driver, two Q 5046 a transistor and two resistors, permggg of which is the collector load of the second transistor connected in a common emitter circuit, characterized in that, in order to expand its functionality, a third transistor, a threshold element, a voltage limiter and an input the control bus, the base of the first transistor, connected according to the scheme, with a common emitter, is connected to the input bus of the device, the collector with the base of the Second transistor and the output of the threshold element, the input of which is connected to the collector of the third transistor and the second resistor, the second output of which is connected to the power source, the output of the voltage limiter connected to the collector of the second transistor and the base of the third transistor whose emitter is connected to the metering capacitor and with output bus. -O i4 H h Uy / rp. I D % / Fi.g Compiled by E.Solovyov Editor P.GorkovTehred M.KhodanychSorrector M-Lemchik Order 4152 Draw 730 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab, 4/5 Production polygraphic enterprise, Uzhgorod, st. Project, 4