Pin Assignments for
LM7805 and 7812

1. V in
2. Ground
3. V out

Components List

Bridge rectifier or 4 diodes 1N4002
Capacitors : C1 = 1000 µF 25 V
C2, C3 = 220 nF
regulators : LM 7812, LM 7805
Adaptor (BS) 500 mA

In the case of a 12 volts battery as electric power supply (we can intend to go to fields with his spectroheliograph), the plan is reduced to the production of a tension regulated to 5 volts.

The use of operational amplifiers also requires the production of negative voltages. Various assemblies are still possible, the simplest being the use of an integrated converter. We can then, from a 5 volts supply, get symmetric voltages 12 and -12 volts.

Components List

Capacitors : C1,C2 = 220µF 25 V
5V regulated power supply
DC/DC converter : PM951

Clock pulse generator / binary counter

This digital circuit (CD 4060) allows to produce a stable square signal of high frequency by means of a quartz and very few secondary components. Its counter function (divide by 2 counter) allows to find one frequencies suited for the clocks of the CCD.

Pin Assignments for CD4060

1. Q12
2. Q13
3. Q14
4. Q6
5. Q5
6. Q7
7. Q4
8. Ground
9. clk2
10. clk 1
11. clk
12. reset
13. Q9
14. Q8
15. Q10
16. +Vcc

Components List

Resistor : R1 = 10 MΩ
Capacitors : C1, C2 = 4.7 pF
Quartz : X1 = 12 MHz
digital circuit : CD 4060

Power supply VCC : 5 to 18 V

Output Qi delivers a frequency equal to the quartz frequency divided by 2 at the power i (ex: Q5 gives Freq / 32)

Changing the pulse width

The previous assembly gives a rectangular signal with a duty cyclic equal to 50 %. We can need to change it to produce pulses for example. A simple means is to use a variable RC circuit and to reshape the signal obtained by means of a Schmidt trigger , here a CD 4093 which allows to use a wide range of voltage. (The CD 4093 is in fact a quadruple logic gates NAND which we use here only the inverter function).

Pin Assignments for CD4093

1. In1
2. In1'
3. Out1
4. Out2
5. In2
6. In2'
7. Ground
8. In3
9. In3'
10. Out3
11. 1Out4
12. In4
13. In4'
14. +Vcc

Components List

Pot. : P1 = 20 kΩ
Capacitors : C1, 33 pF
digital circuit : CD 4093

Power supply VCC : 5 to 18 V

Modifying the value of P1 we make vary the height of the signal (B) which is not any more squarewave but sawtooth. The trigger activates when a threshold is reached and we so obtain a modified duty cycle (C and D).

PWM generator (pulse width modulation)

Here is an assembly very simple to get an oscillator giving a fixed frequency signal but variable duty cycle. It can - after amplifier transistor - serve to control the rotation speed of a motor with direct current or to adjust the power of a dew-heater. We use once again a logic gate of a CD4093 circuit.

Pin Assignments for CD4093

1. In1
2. In1'
3. Out1
4. Out2
5. In2
6. In2'
7. Ground
8. In3
9. In3'
10. Out3
11. Out4
12. In4
13. In4'
14. +Vcc
    

Components List

Pot. : P1 = 220 kΩ
Capacitors : C1, 0.47 µF
diodes 1N 4148
resistor 2.2 kΩ

digital circuit : CD 4093

Power supply VCC : 5 à 15 V

The frequency of oscillations is easily modifiable by changing the value of the capacitior. The unused pins of the CD4093 must be connected to ground.

Amplification of video

The video signal going out of the CCD is low level and it is necessary to amplify it to allow a good transmission in a long cable.

Components List

Resistors :
R1 = 100 Ω, R2 = 1 KΩ
Transistor : T1 = 2N2222

The voltage of the video signal varies the other way of the illumination. It is thus necessary to invert this signal and to move its origin so that the voltage is equal to 0 for a no illumination and so that it increases when the illumination increases. The operational amplifiers are the ideal solution for this work.

Pin Assignments for TL082

1. out 1
2. inv inp 1
3. non-inv inp 1
4. -Vcc
5. non-inv inp 2
6. inv inp 2
7. out 2
8. +Vcc

Il y a donc 2 amplis-op dans ce boitier.

Components List

Resistors : R1 = 1 kΩ, R2,R3 = 2,2 kΩ, R4 = 470 Ω
Pot. : P1,P2 = 10 kΩ
Capacitors : C1 = 10 nF
Op-Amplifier : TL 082

circuit R4,C1 circuit is a filter able to limit high frequencies.

Analogic / Digital converter

This integrated circuit (AD 7821) allows to convert an analogic signal in a 8 bits value with a 1 µs conversion time, thus with a 1 MHz frequency. There are faster converters allowing to obtain a better resolution (10, 12, 14 or 16 bits).

Pin Assignments for AD7821

1. Input
2. Data bit 3
3. Data bit 2
4. Data bit 1
5. Data bit 0
6. WR/RDY
7. Mode
8. RD
9. INT
10. Ground
11. Vref -
12. Vref +
13. CS
14. Data bit 4
15. Data bit 5
16. Data bit 6
17. Data bit 7
18. OFL
19. Vss
20. +Vcc

Components List

Pot. : P1 = 20 kΩ
A/D Converter = AD7821
trigger inverter = 1/4 CD4093

The signal resulting from the amplifier is applied to the pin 1 (Input). The reference voltage is adjusted by means of P1. It is very summary but that works. We can also use a specific component to obtain this reference voltage (zener diode for ex.).

The pulse "start of conversion" results from the clock generator (having a 5 V level compatible with the converter) and the pulse "End of conversion" is sent to the PC interface, as well as 8 bits data. We can also send these data through buffer circuits (74245 by eg) to secure the exchanges interface-converter. The logic gate (1/4 CD4093) can be another inverter.

Stepper motor drive

Integrated circuits intended to drive stepper motors are many and are rather easy to operate because they contain both logical circuits and power circuits in the same chip. You just have to choose the circuit corresponding to the type of stepper motor you want to use, namely unipolar (6 wires) or bipolar (4 wires).
In the first case, we can use a SAA on 1027 (difficult to find now) or a more powerful UCN 5804. For the bipolar motor, the SAA 1042 (idem) or the MC 3479 will be quite indicated. Most of these controllers allow to work in half-step mode.

It is to note also that we can drive a unipolar motor with a controleur for bipolar motor but that the opposite is not possible.

We propose here a plan of driver for unipolar motor realized with 2 common logic components and a power circuit. It is possible to drive motor needing 500 mA by coil, what should be sufficient in the present frame!

Pin Assignments for CD4070

1. In 1
2. In 1'
3. Out 1
4. Out 2
5. In 2
6. In 2'
7. Ground
8. In 3
9. In 3'
10. Out 3
11. Out 4
12. In 4
13. In 4'
14. +Vcc

Pin Assignments for CD4013

1. Out 1
2. Out inv 1
3. Clock 1
4. Reset 1
5. Data 1
6. Set 1
7. Ground
8. Set 2
9. Data 2
10. Reset 2
11. Clock 2
12. Out inv 2
13. Out 2
14. +Vcc

Pin Assignments for CD4093

1. In 1
2. In 2
3. In 3
4. In 4
5. In 5
6. In 6
7. In 7
8. Ground
9. +Vcc
10. Out 7
11. Out 6
12. Out 5
13. Out 4
14. Out 3
15. Out 2
16. Out 1

Components list

IC :
quad. XOR = CD 4070 or 4030
Dual shift register = CD 4013
Ampli = ULN 2003
Unipolar stepper motor

Stepper motors can be found on old floppy disk drives or printers for example. In certain cases we can even use the controllers who are joined to it. 2 control pulses can result from a microcomputer (parallel port) + line buffers.

Other intergated circuits

Pin Assignments for 7414

1. In 1
2. Out 1
3. In 2
4. Out 2
5. In 3
6. Out 3
7. Ground
8. Out 4
9. In 4
10. Out 5
11. In 5
12. Out 6
13. In 6
14. +Vcc
    
    

Pin Assignments for LM358

1. out 1
2. inv inp 1
3. non-inv inp 1
4. GND
5. non-inv inp 2
6. inv inp 2
7. out 2
8. +Vcc

dual monotension opAmpli : LM358

+VCC from 5 to 15V