For the correct determination of parameters of source of current sometimes it is necessary to increase the measurement accuracy of its electromotive force. For this purpose it is necessary to use voltmeters of more high-class accuracy or to use special schemes on amplifiers of direct current. If on entrance of such amplifier the field transistor is installed, the input resistance of the amplifier will be very high in comparison with the output resistance of source of current and the error at measurement will be insignificant.
It is required to you
- - 2 KP103K transistors;
- - 2 resistors 3.6 kOhm;
- - resistor 4.7 kOhm;
- - resistor 4.7 my;
- - resistor 2 kOhm;
- - variable resistor 10 kOhm;
- - tuning resistor of 51 kOhm;
- - switch;
- - connecting wires;
- - soldering iron of 25 Watts;
- - rosin and tin;
- - voltmeter.
Instruction
1. Solder one conclusion together resistors 4.7 my, 4.7 kOhm and 2 kOhm. Solder together drains of transistors and the second resistor termination 2 kOhm. Solder lock of the first transistor to free resistor termination 4.7 my, and lock of the second transistor solder 4.7 kOhm to free resistor termination.
2. 10 kOhm solder conclusion of the toddler of the variable resistor to power switch conclusion. Free conclusions of the variable resistor 10 kOhm solder 3.6 kOhm to resistors. Free resistor termination 3.6 kOhm, the tuning resistor of 51 kOhm and source of the first transistor solder together. Solder free conclusion of the second resistor 3.6 kOhm to source of the second transistor.
3. Solder together free conclusions of the tuning resistor of 51 kOhm and connect to negative conclusion of the voltmeter. Connect positive conclusion of the voltmeter to source of the second transistor. Turn on the voltmeter in the range of strain measurement from 0 to 1 Volta.
4. Connect free conclusion of the switch to negative battery lead of power supply. Solder positive conclusion to the resistor terminations soldered together 4.7 my, 2 kOhm and 4.7 kOhm. Make the battery of power supply of connected in series three elements 3336 of 4.5 Volts. The amplifier keeps working capacity at voltage drop of the battery to 9 Volts.
5. This amplifier is calculated on measurement of constant voltage ranging from 0 up to 1 Volta. Input resistance is more than 4 my. For measurement of big tension make high-resistance voltage dividers: for measurement of tension within 10, 100 and 1000 Volts 1:10, 1:100 and 1:1000 respectively.
6. For mounting of the amplifier (especially dividers) use material with high insulating properties. For dividers manufacture the separate body. For check of supply voltage of the amplifier make separate divider with ratio 1:15. Mount it in the same body, as the amplifier. Install the non-locking button working for short circuit. Via this button connect divider to amplifier entrance. Now you at any time will be able to check condition of the battery.