Hi i need help with a frequency meter im trying to build, i have a 100uA anologue movement with a resistance of around 2K ohms and a frequency transducer circuit to make the instrument read 340-440hz at 200v on the scale ,but i am having problems with it it is very unstable, everytime i calibrate it then connect it to equipment to check it 30 mins later it is out of cal and i would like some help in making it more stable mb by using different components or adding a couple more. I can submit pictures of circuit layout and component list if someone out there is prepared to help.Also when i set the voltage at the start of calibrating do i need to adjust it back to 200v after the instrument is powered up or do i leave it alone as there will be a substantial voltage drop once meter is connected and powered up? If i check voltage after bringing it back up to 200v while meter is disconnected it reads 440v surely this cant be right!! I want instrument to work at 200v so do i leave voltage alone after i have connected it at 200v , the multimeter says its only 95-98v can this be right? please get back to me.
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