Circuit Diagram 1
Circuit Diagram 2
Circuit Diagram 3
Description
Description
Even if
the digital multimeters have dominated in a lot of applications, in the measurement, exist
the need for existence of instruments of clue in various appliances, voltage and current,
as in power supply or elsewhere. The circuits that give make this precisely the work,
measure the voltage in terminal a circuit and the current that passes in his. The circuit
does not present particular difficulties for somebody that has a small experience. The two
circuits are the himself, with a small difference only in their input, when they have they
measure voltage or current and in connection that concern decimal point [ dp ]. In the
department of input IC1 and IC3, exist the CA3161E, that is a A/D Converter for 3-Digit
Display. In the drive of Display IC2 and IC4, exist CA3161E, that is a BCD the Seven
Segment Decoder/ Driver. As it appear in Fig.1, that concern the voltmeter in input [ + IN
], exist in series a what resistor R1 in combination with the R3 create a voltage divider.
On the contrary in the Fig.2 that it concern the ampere meter, this resistor does not
exist, because the circuit is connected differently, thus the current pass through the R5,
creating a fall of voltage, in her terminal, proportional current that it pass from this.
Adjustments
Voltmeter: Short circuit in the input, pins 10
and 11 [IC1] and we regulate the RV1, until we take clue in the Display, zero in all the
digits. We rectify and connect in the input a external voltage roughly 900mV. With the
RV2, we regulate so that we take the clue 900mV in the Display. At the same time, we check
this voltage with a external multimeter, of good quality and precision.
Amperemeter: Short circuit in the input, pins
10 and 11 [IC3] and we regulate the RV4, until we take clue in the Display, zero in all
the digits. We rectify and we connect in + IN point, provided that we place in series with
the positive pole, of battery, a resistor 10R/10W and in the –IN, a new battery 9V. We
regulate the RV3 so that we take clue in the Display 0.90A. We check simultaneously the
correctness of measurement with a external digital ambermeter. A point that it
should we are careful, the capacitors C4 and C9, it should they are very good quality.
Also the various in the placement of resistors R4 and R7. of connection two circuits, for
measurement voltage and current, appear in the Fig.3. The power supply that is public for
two circuits appears in the Fig.4. If exist suitable constant supply in the appliance in
which will be placed permanently the circuits, then can remove the T1 and bridge GR1 and
is connected this voltage, in point A. The IC5 good is placed in heatsink.
Feature
V in maximum: 100V [99.9V]
A in maximum: 10A
[9.99A]
Max. measurement Voltage Error: 100mV
Max. measurement Ampere Error: 100mA| Part List |
| R1=680Kohms | C1-5=10nF | IC2-4=CA3161E Intersil-Harris |
| R2-6=1Mohms | C2-6=47uF 16V | IC5=7805 |
| R3=6.8Kohms | C3-7-10-11=100nF | GR1=4X 1N4001 |
| R4-7=270 ohms | C4-8=220nF 1% | Q1......6=BC557 |
| R5=0.1 ohms 5W | C9=2200uF 25V | DS1......6= 7Segment Display common anode |
| RV1-4=50Kohms trimmer 10 turns | C12=10uF 16V | T1=230VAC/6VAC 1A |
| RV2-3=5Kohms trimmer 10 turns | IC1-3=CA3162E Intersil-Harris |
+ comments + 2 comments
this will surely help in my studies and in my exams too. thank you so much for sharing this info. about ampere meter. cheers!
this will surely help in my studies and in my exams too. thank you so much for sharing this info. about ampere meter. cheers!
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