1. Block Diagram Nikon (on-focal ) microscope Electronic Box NI： DAQ card
Including：
Voltage Follower
Low-pass Filter
Voltage Difference Amplifier
NI：
DAQ card
(model #：PCI-6010)
& LabVIEW PC
LabVIEW software
PMT
Signal

2. Operational Amplifier：OP 27
Low noise, low drift, low offset
Supply voltage ( )：±12V (old design) / ±15V (new design)

3. Voltage Follower
Change the output impedance while the output voltage equals to the input one.
Vsig
Vout

4. Butterworth Low-pass Filter
Synthesize a fourth-order Butterworth low-pass filter by cascading two second-order low-pass section.
Cut off Frequency: f Hz
Ref：J. Millman, “microelectronics：digital and analog circuits & systems” pp (1979)
10 k
1.52 k
10 k
12.35 k
2 k k
2 k
2 k
Vout
Vsig 1μ 1μ 1μ 1μ

5. Voltage Difference Amplifier
Amplifying the difference between two inputs by a gain factor.
Here Vref is adjustable offset voltage
Note that this circuit applies to negative signal input (old design) Rf
Vsig R
+Vcc
Vout R Rf
Vref
-Vcc
Vout = (Vref - Vsig)*

6. Voltage Difference Amplifier
Amplifying the difference between two inputs by a gain factor.
Here Vref is adjustable offset voltage
Note that this circuits applies to positive signal input (new design) Rf
+Vcc
Vref R
Vout
-Vcc
Vsig R Rf
Vout = (Vsig - Vref)*

7. Electronic Circuit Layout (old design)
1.52K (502)
12.35K (503)
10K
10K
1000K
100K 2K 2K 2K 2K
+Vcc
100K
Signal Output
≦ 5 V 1μ
Signal Input
(from detector)
Signal ＜ 200 mV 1μ 1μ
1000K 1μ
(503)
-Vcc

8. Electronic Circuit Layout (new design)
1.52K (502)
12.35K (503)
10K
10K
1000K
100K 2K 2K 2K 2K
100K
Signal Output
≦ 5 V 1μ
Signal Input
(from detector)
Signal ＜ 200 mV 1μ 1μ
1000K
To panel potential meter 1μ

9. Voltage Meter Driver = Non-inverting Amplifier
To drive the voltage meter ( Reason：to match the meter scale )
Vout = Vin * ( ) =
Variable Resistance (50K)
Vsig R1 R2
Vsig
Output

10. Calibrate the Voltage Meter Scale
PMT, Monitor and the Voltage Meter should possess linear relationships
Adjust the gain (ratio of R1 / R2) of the non-inverting amplifier with different PMT values
PMT Voltage Range：0~1000V
Monitor Signal Range：0~4V
Voltage Meter Reading：0~10V
For example：
PMT Voltage
Monitor Signal
Voltage Meter Reading
250 V
1 V
2.5 V
500 V
2 V
5.0 V
750 V
3 V
7.5 V
1000 V
4 V
10.0 V

11. Power Line Wiring in the Electronic Box (old design)
L：red line
N：blue line
G：green line G 1 N L 2
switch 3
L N G -V +V com +5V
L N G -V +V
±12V
+15V

12. Power Line Wiring in the Electronic Box (new design)
L：red line
N：blue line
G：green line G 1 N L 2
switch 3
L N G -V +V com +5V
±15V

13. Electronic and Panel Wiring (old design)
To Electronic Circuit V+ V-
+5V (not used)
Vcom
+12V
-12V
+15V Power Supply
±12V Power Supply
Connect to the output of the voltage meter driver
Connect to the input of the voltage meter driver
To Electronic Circuit - +
+15V Output
(To PMT)
PMT Voltage Monitor
PMT Signal Input
Signal Output (To DAQ)
Signal Offset
Voltage meter

14. Electronic and Panel Wiring (new design)
To Electronic Circuit
+5V (not used)
Vcom
+15V
-15V
±15V Power Supply
Connect to the output of the voltage meter driver
Connect to the input of the voltage meter driver
To Electronic Circuit - +
+15V Output
(To PMT)
PMT Voltage Monitor
PMT Signal Input
Signal Output (To DAQ)
Signal Offset
Voltage meter

15. Electronic Testing multi-meter ：
check the circuit before connecting to the power supply.
function generator & oscilloscope ：
check whether the output of each component satisfies our expectation：
a. Each OP Amp should function properly！(make sure
the pins have right voltage.)
b. Voltage Follower：should be exactly the same
with the input.
c. Low-pass Filter：should filter out the signals with
frequency higher than 80 hz.
d. Voltage difference amplifier：should amplify our
signals with the designed gain factor.

16. Circuit Layout 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 IN
OUT
OFFSET
Voltage Meter
：To V+
：To V-
：To Vcom (ground)
：To the panel
：two points connected
：wired

17. Testing the Frequency Response
With fixed amplitude sinusoidal wave signals, we can test how the electronic circuit box low-pass filter responds to the sinusoidal wave frequencies.
Function Generator
Oscilloscope
Freq.
OUTPUT
Ch.1
Ch.2
Electronic Circuit Box
Input Signal
Output Signal

18. Experimental Frequency Response
Input : 100 mV, sinusoidal waves
-3 dB 75

19. Part List in the Electronic Box
Item
Quantity
OP 27 (with 8-pin socket) 5
Capacitor (1μF) 4
Resistor (2 kΩ)
Resistor (10 kΩ) 2
Resistor (100 kΩ)
Resistor (1000 kΩ)
Adjustable resistance (5 kΩ) 1
Adjustable resistance (50 kΩ)
Ten turns potential meter
BNC
110 V socket
110 V switch with indicator
10 V DC voltage meter
Power supply (±15 V)