SU1229594A1 - Digital thermometer - Google Patents

Abstract

The invention relates to temperature measurements. The purpose of the invention is to extend the measurement range to negative temperatures and to determine the sign of the temperature to be measured. The thermometer contains a thermal converter 1, an amplifier 2, generators 3 and 4 sawtooth voltages, comparators (K) 5 and 6, keys (K) 7 and 8, circuit OR 9, frequency divider (QH) 10, pulse counters (SI) 11, the decoder (D) 12, the display unit (BI) 13, the trigger 14 characters and the generator 15 clock pulses. Depending on the polarity of the measured temperature and on the duration of the pulse received by the K 5 or 6 clock, the clock pulses pass through K 7 or 8 and DCH 10 in SI 11. The number of pulses counted by the SI during the pulse time is proportional to the temperature being measured. This number is indicated by D 12 in BI 13, 1 Il. with f & (L Run f6

Description

The invention relates to the field of measurement measurement temperatures, in particular to digital thermometers.

The purpose of the invention is to extend the measurement range towards negative temperatures and to determine the sign of the measured temperature.

The drawing shows a structural diagram of a digital thermometer.

The digital thermometer contains a thermal converter 1, for example, a thermoelectric converter or a thermal converter of resistance included in the current source circuit, amplifier 2, first and second generators 3 and 4 sawtooth voltages, two comparators 5 and 6, two switches 7 and 8, OR circuit 9, the frequency divider 1, the pulse counter 11, the decoder 12, the display unit 13, the trigger of the siak 14 and the generator 15 clock pulses.

The thermometer works as follows.

With the appearance of a trigger pulse.

The startup circuit is not shown) at control input 16, the counter 11 is set to the zero state, and simultaneously the generators 3 and 4 of the sawtooth direction and the 15 clock pulses are started.

The generator 3 generates a positive pulse, and the generator 4 a negative polarity pulse.

Thermocoupler 1 exposes a constant voltage, the sign of which corresponds to, and the value is directly proportional to the measured temperature. This voltage is amplified by the amplifier and fed to the first comparators 5 and 6, the second inputs of which receive signals from the outputs of the sawtooth generators.

Comparators 5 and 6 are triggered at the time of equality of the voltages at their inputs, while the pulses at the outputs

I comparators have different polarity and their duration is directly proportional to the measured temperature.

The pulses of positive or negative polarity, depending on the polarity of the output signal of the thermal converter, arrive at the setup inputs of the trigger, 14 characters,

. setting it to

 corresponding to the sign of the measured temperature: one at positive temperature and zero at negative temperature, which is recorded in the display unit 13.

At the same time, the pulse from the output of the comparator 5 or 6 goes to the second

inputs of keys 7 and 8, the first inputs of which receive clock pulses from generator 15. Depending on the polarity of the measured temperature and the pulse duration received at the output of comparator 5 or 6, clock pulses pass through key 7 or 8 and divider IO in the counter 11 pulses. The number of pulses counted by a pulse counter for

the duration of the pulse is directly proportional to the measured temperature. This number is indicated by the decoder 12 in the display unit 13.

Claims (1)

Invention Formula A digital thermometer containing a thermoconverter, two keys, the first inputs of which are connected to the output: - one of the clock generator, the first comparator, the first input of which is connected to the output of the first generator of the sawtooth voltage, and the output connected to the second input of the first key, in series included frequency divider, pulse counter, descrambler and display unit. 0 five This is in line with the fact that, in order to extend the range of measurement 5 towards negative temperatures. A voltage amplifier, an OR circuit, a second sawtooth generator, a sign trigger and a second comparator, whose inputs are respectively connected to the output of the second sawtooth generator and a second input of the first comparator, are connected to the output of the voltage amplifier, whose input is connected to thermal converter, the output of the second comparator is connected to the second input of the second key and the first input of the character trigger, the second input of which is connected to the output of the first comparator, and the output is connected to the input of the block In the display, the outputs of the keys are connected respectively to the inputs of the SHS circuit, output1) of which is connected to the frequency divider, and the control input of the pulse counter is connected to the inputs of the start of the clock generator and sawtooth voltage generators. 0 five