gres
Full Member level 4
Measure instrument can check voltage of device that is plugged to. It consist full package of current dividers and can be powered from wide range. It has secure system against wrong power connection and secure system for measured inputs against too high voltage.
Range can be choose by jumper:
5V- from 3,6V to 7V. It works also with 2,8V but is sensitive for power jumps.
40V – from 5,5 to 40V. It works with 4,5 but there is the same problem.
You can decrease a little bit range of power voltage, by shorting secure diodes. With range 5V we’ll get 0,2 and with 40V about 0,5. instrument can be also powered by higher source. To do that you need add an Zener’s diode for example : from 100V we need diode for 70-80, so we will get 200mW of heat.
Current takie in 5V is smaller than 800uA, and with 40V is about 2,2V. higher voltage you need for LM317L, that is minimal current for it.
Instrument consist 4 checking range: 200mV without jumper, or 2V, 20V, 200V with jumpers. To change range you may use outside switchers.
Dimensions of the tool : 69mmx 37mm x deep 15mm
What you can’t do :
1. Lo input you cant mix with Hi, this is not a analogue instrument. Lo always has ground or about +/-2V.
2. you can’t plug power via switcher, when power source is higher than 20V. instrument should be constantly plug to power. Lm317L doesn’t like when voltage grow up too fast.
Good advise is to solder an electrolytic condenser with secure diode to the ground.
At https://www.elektroda.pl/rtvforum/topic1579978.html you can find more informations and some diagrams for those who like to solder.