Article
V & I Calibrator
Have faith in your measurements
It’s difficult to be sure that your digital multimeter (DMM) is taking accurate measurements especially if it’s a few years old. This handy calibrator gives full scale reference levels of both voltage and current, designed specifically for the scale ranges used by DMMs.
DMMs which claim to have a basic accuracy better than 1% can these days be found for less than £20. Even instruments with better than 0.5 % accuracy are selling for less than £100.
DMMs which claim to have a basic accuracy better than 1% can these days be found for less than £20. Even instruments with better than 0.5 % accuracy are selling for less than £100.
Materials
Gerber file
CAM/CAD data for the PCB referred to in this article is available as a Gerber file. Elektor GREEN and GOLD members can exclusively download these files for free as part of their membership. Gerber files allow a PCB to be produced on an appropriate device available locally, or through an online PCB manufacturing service.
Elektor recommends the Elektor PCB Service service from its business partner Eurocircuits or AISLER as the best services for its own prototypes and volume production.
The use of our Gerber files is provided under a modified Creative Commons license. Creative Commons offers authors, scientists, educators and other creatives the freedom to handle their copyright in a more free way without losing their ownership.
PCB
Extra info / Update
Technical Specifation
• 0.1 % accuracy at 25°C
• Temperature stability: 50 ppm/°C
• Output voltage: 3.9 V/1.9 V switchable
• Output current: 3.9 mA/1.9 mA switchable
• Power requirements: 6 to 18 VAC or 9 V battery
• Current consumption: 5 mA
• 0.1 % accuracy at 25°C
• Temperature stability: 50 ppm/°C
• Output voltage: 3.9 V/1.9 V switchable
• Output current: 3.9 mA/1.9 mA switchable
• Power requirements: 6 to 18 VAC or 9 V battery
• Current consumption: 5 mA
Component list
Resistors
R1 = 1k?5, SMD R1206
R2 = 3k?9, 0.1%
R3A = 68k?, 0.1%
R3B = 10k?, 0.1%
R4A = 2k?7, 0.1%
R4B = 680?, 0.1%
R5 = 1k?, 0.1%
Capacitors
C1 = 100?F 35V, radial electrolytic
C2 = 10?F 35V, radial electrolytic
C3,C4 = 100nF, SMD C1206
C5 = 10nF, SMD C1206
C6 = 1nF, SMD C1206
Semiconductors
B1 = B40S, SMD bridge rectifi er, 40V/1A
IC1 = 78L05SMD, SO08
IC2 = LT1490, SO08
IC3 = LM4050A-4.1, SOT-23, e.g. Farnell # 1468851
Miscellaneous
JP1 = 3-way SIL pinheader, lead pitch 2.54mm (0.1”) with jumper
PCB, # 080894-1
R1 = 1k?5, SMD R1206
R2 = 3k?9, 0.1%
R3A = 68k?, 0.1%
R3B = 10k?, 0.1%
R4A = 2k?7, 0.1%
R4B = 680?, 0.1%
R5 = 1k?, 0.1%
Capacitors
C1 = 100?F 35V, radial electrolytic
C2 = 10?F 35V, radial electrolytic
C3,C4 = 100nF, SMD C1206
C5 = 10nF, SMD C1206
C6 = 1nF, SMD C1206
Semiconductors
B1 = B40S, SMD bridge rectifi er, 40V/1A
IC1 = 78L05SMD, SO08
IC2 = LT1490, SO08
IC3 = LM4050A-4.1, SOT-23, e.g. Farnell # 1468851
Miscellaneous
JP1 = 3-way SIL pinheader, lead pitch 2.54mm (0.1”) with jumper
PCB, # 080894-1
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