Sorry for my awful english.
I need some help understanding ESR meter adjustment
i have Elektor 2002/9 ESR METER?
It says in there magazine
ESR Tester adjustment
Before adjusting the instrument, be
sure that you have a regulated plus
5 V from IC5 and minus 5 V from
IC7. If you don’t, you’ll have to troubleshoot
your circuit board.
1. Start with the voltmeter circuit.
P1 should be disconnected at this
point. Connect a known, accurate
voltage source of less than 200
mV to point TPA (test point A)
and adjust P5 until the LCD
shows the right value. Remove the voltage source. Connect TPA to TPB,
short the test leads together, and adjust
P2 for a ‘000.0’ reading. Remove the connection.
Reconnect P1.
2. Connect a frequency counter or an oscilloscope
between TPC and GND. Adjust P4
for 200 kHz counter reading or 5 µS
period time on the oscilloscope.
1-)With DMM i could measure IC5 and IC7 components +- 5 volts.
2-)I desoldered P1 and
3-)I set the power supply to 0.150 V and attached one of the crocodile connecter to TPA but i don't know which part the other one will be connected?And which part is GND on the circuitboard?
4-)Do we need to fallow exact adjustment part 2? Which has needed some oscilloscope and frequency counter measurments?
Thanks a lot