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A TRANSISTOR PULSE COUNTER
Brit. J. Anaesth. (1955), 27, 261.
A TRANSISTOR PULSE COUNTER BY L . MOLYNEUX AND E. A. PASK
Department of Anaesthetics, Medical School, King's College, University of Durham
FIG.
strument which we now have in use is shown. The advantages gained from the use of transistors seem to be as follows: (1) Compact dimensions. Our instrument is 10" high, 7i" wide and 5" deep.
1
Downloaded from http://bja.oxfordjournals.org/ at University of Iowa Libraries/Serials Acquisitions on May 26, 2015
can be used to construct a cardiotachometer with characteristics more favourable than those hitherto available. The photograph (fig. 1) and circuit diagrams (figs. 2 and 3) of an inTRANSISTORS
262
BRITISH JOURNAL OF ANAESTHESIA
• A
1.
2. 3. 4.
1.0 390 820 2.7 1. 2. 3.
5. 6. 7. 8.
0.1
0.25 8.0
2.7 1.5 82 20 4. 5. 6.
21. 22. 23. 24. 0.5 0.5 0.5
33 27 12 20
16. 17.
25.
33
26.
5.6
100 0.5
Fio. 3 1. 2. 3.
100 22 20
1.
0.5
4. 5. 6. 2.
Resistances in kilohms 0.11 7. 0.32 10. 5.6 15
8.
470 6.8
11. 12.
9. Capacities in microfarads
1.0
Transistors 1, 2 and 3 are Mullard Type OC71. 4 is Mullard Type OC51
3.
0.1
4.
1.0 1.0
0.22
13. 14. 15.
0.25
2.7 1.0
5. 2000 Diodes All Diodes are Mullard Type OA73
6.0
Downloaded from http://bja.oxfordjournals.org/ at University of Iowa Libraries/Serials Acquisitions on May 26, 2015
Fro. 2 Resistances in kilohms 9. 12 40 13. 40 17. 10. 82 14. 27 27 18. 11. 27 15. 82 12 19. 20 1Z 20 16. 20 20. Capacities in microfarads 7 0.5 13. 0.25 10. 100 100 8. 0.5 14. 11. 0.5 0.5 9. 0.5 15. 12. 0.5 Transistors 1, 2, 3 and 4 arc Mullard Type OC71
A TRANSISTOR PULSE COUNTER
The large upper dial continuously displays the pulse rate. The needle of the smaller dial flicks each time the heart beats, so that irregularities are immediately evident. The small loudspeaker, lower left, makes a tiny click every time the heart beats. The amplitude of this click can be controlled. Connexion to the patient is made either by conventional ECG leads or by sterile needles inserted in the skin of the chest.
ST. JOSEPH HOSPITAL, HEERLEN, LIMBURG, HOLLAND ANAESTHETIST WANTED, well qualified and trained, who would replace the Hospital Anaesthetist during his three weeks holiday from August 1 till August 21, 1955. Write all particulars, including references, to Medical Director, H. H. Lindeboom, St. Joseph Hospital, Heerlen, Limburg, Holland.
Downloaded from http://bja.oxfordjournals.org/ at University of Iowa Libraries/Serials Acquisitions on May 26, 2015
(2) Light weight. Our instrument weighs 8i lb. (3) Very economical. Battery operation (total consumption 48 milliwatts). The expected life of internal batteries is in excess of 50 hours. (4) Because the battery voltage is low, the instrument presents no explosive hazard. (5) No leads are needed other than those from the instrument to the patient.
263
A TRANSISTOR PULSE COUNTER BY L . MOLYNEUX AND E. A. PASK
Department of Anaesthetics, Medical School, King's College, University of Durham
FIG.
strument which we now have in use is shown. The advantages gained from the use of transistors seem to be as follows: (1) Compact dimensions. Our instrument is 10" high, 7i" wide and 5" deep.
1
Downloaded from http://bja.oxfordjournals.org/ at University of Iowa Libraries/Serials Acquisitions on May 26, 2015
can be used to construct a cardiotachometer with characteristics more favourable than those hitherto available. The photograph (fig. 1) and circuit diagrams (figs. 2 and 3) of an inTRANSISTORS
262
BRITISH JOURNAL OF ANAESTHESIA
• A
1.
2. 3. 4.
1.0 390 820 2.7 1. 2. 3.
5. 6. 7. 8.
0.1
0.25 8.0
2.7 1.5 82 20 4. 5. 6.
21. 22. 23. 24. 0.5 0.5 0.5
33 27 12 20
16. 17.
25.
33
26.
5.6
100 0.5
Fio. 3 1. 2. 3.
100 22 20
1.
0.5
4. 5. 6. 2.
Resistances in kilohms 0.11 7. 0.32 10. 5.6 15
8.
470 6.8
11. 12.
9. Capacities in microfarads
1.0
Transistors 1, 2 and 3 are Mullard Type OC71. 4 is Mullard Type OC51
3.
0.1
4.
1.0 1.0
0.22
13. 14. 15.
0.25
2.7 1.0
5. 2000 Diodes All Diodes are Mullard Type OA73
6.0
Downloaded from http://bja.oxfordjournals.org/ at University of Iowa Libraries/Serials Acquisitions on May 26, 2015
Fro. 2 Resistances in kilohms 9. 12 40 13. 40 17. 10. 82 14. 27 27 18. 11. 27 15. 82 12 19. 20 1Z 20 16. 20 20. Capacities in microfarads 7 0.5 13. 0.25 10. 100 100 8. 0.5 14. 11. 0.5 0.5 9. 0.5 15. 12. 0.5 Transistors 1, 2, 3 and 4 arc Mullard Type OC71
A TRANSISTOR PULSE COUNTER
The large upper dial continuously displays the pulse rate. The needle of the smaller dial flicks each time the heart beats, so that irregularities are immediately evident. The small loudspeaker, lower left, makes a tiny click every time the heart beats. The amplitude of this click can be controlled. Connexion to the patient is made either by conventional ECG leads or by sterile needles inserted in the skin of the chest.
ST. JOSEPH HOSPITAL, HEERLEN, LIMBURG, HOLLAND ANAESTHETIST WANTED, well qualified and trained, who would replace the Hospital Anaesthetist during his three weeks holiday from August 1 till August 21, 1955. Write all particulars, including references, to Medical Director, H. H. Lindeboom, St. Joseph Hospital, Heerlen, Limburg, Holland.
Downloaded from http://bja.oxfordjournals.org/ at University of Iowa Libraries/Serials Acquisitions on May 26, 2015
(2) Light weight. Our instrument weighs 8i lb. (3) Very economical. Battery operation (total consumption 48 milliwatts). The expected life of internal batteries is in excess of 50 hours. (4) Because the battery voltage is low, the instrument presents no explosive hazard. (5) No leads are needed other than those from the instrument to the patient.
263