Africa-focused technology, digital and innovation ecosystem insight and commentary.
Manage episode 271041992 series 120573
- Got a fully automatic screen printer!
- ESE US-2000X
- Potentially lower our minimal paste size
- Twitch Live Stream podcasts?
- Amazon multimeter probes
- High voltage low current measurement
- Don't want to break the connection so a traditional ammeter isn't going to work
- Sticking with the read both sides of a resistor method
- Caddock 1776-C681 high voltage high resistance high tolerance divider
- 1/100 so 0 to 500v becomes 0 to 5v
- ADC - MCP3551-E/SN
- 22 bit
- 2.4 meg ohm input impedance
- Ideally the voltage divider has a “gain” of 0.01 but if the ADC is directly attached to the divider the gain is around 0.0096
- Full scale would be 4.8V instead of 5V
- Solution: add a buffer
- Quad buffer
- Typical offset voltage of 100uV
- Gain error of 0.03% max on +/-15v rails
- 10T ohm and 4pf input resistance/capacitance - 10^12
- Gain error is now 0.009999999901 - Close enough