The tools of science are basically extensions of the operator`s senses. They allow us to measure quantities so large or so small that they cannot be examined directly. In many fields the oscilloscope has become an indispensable tool for the scientist or technician. It enables him to make quantitative and qualitative measurements of electrical phenomena not readily measurable by other means.

Manipulation of the front-panel controls of an oscilloscope can be learned by rote. To use the instrument to its fullest capabilities a knowledge of oscilloscope circuitry is essential.

The purpose of this book is to introduce the reader to basic oscilloscope circuitry. It is written specifically for persons who begin with only a rudimentary knowledge of electronics. An understanding of the function of electronic components is developed before the reader is introduced to circuitry. No attempt to make a complete mathematical analysis of each case will be found: rather, we have presented the mathematics necessary for the reader to understand and apply the principle set forth.

While the book has been written as outlined above, we feel that the competent technician will find much here to enhance his understanding of the instrument will benefit from the information gained.

Finally, this is a first attempt on our part to present this type of information. We welcome comments on this book and would be interested in adding information if it seems desirable.

Tektronix, Inc.

CHAPTER 1
PULSE VOLTAGES AND CURRENTS

Some quantities of interest in pulse studies ● General mature of a pulse source ● Responses to current and voltage pulses ● Pulse responses of resistors ● Back emf in an inductor ● Slope of a current or voltage waveform ● Derivative or current ● Derivative at a single point on a waveform ●Graph of the derivative of a voltage or current ● Response of an inductor to a current pulse ● Response of an inductor to a voltage pulse; the slope problem reversed ● Integrals ● Dc component ● Responses of capacitors to applied pulses

CHAPTER 2
SQUARE-WAVE TESTING

Square-wave testing ● The RL circuit ● Time constant ● Other curves ● The RC circuit ● Interstage-coupling system ● Shunt capacitance ● Leading edge of an amplified square wave ● Risetime ● Risetime measurements ● Flat top of the amplified square wave ● Falltime of the amplified square wave ● Harmonic composition of periodic pulses ● Information contained in a square wave ●Square-wave observations ● Frequency-response curves ● Relation between risetime and bandwidth ● Oscilloscope bandwidth requirements ● Time-constant curves

CHAPTER 3
DIFFERENTIATING AND INTEGRATING CIRCUITS

Some typical needs for differentiating and integrating circuits ● The inductive differentiator ● The RC differentiator ● The capacitive integrator ● Another look at integration

CHAPTER 4
INPUT CIRCUITS

Loading of source by oscilloscope vertical-input circuit ● Voltage-divider probes ● Some important thoughts on the use of probes ● Need for adjusting the vertical-input capacitance ● Control of the vertical-deflection factor ● Compensated voltage dividers ● High-voltage probes ● How to display current waveforms

CHAPTER 5
PALTE-LOADED AMPLIFIERS

Voltage gain ● Output impedance ● Input capacitance ● Peaking or compensating circuits ● Shunt peaking ● series peaking ● Combination peaking ● Square-wave response versus high-frequency response ● Low-frequency response ● Dc levels ● Voltage dividers for setting dc levels ● Permanence of gain and dc level ● Grounded-giid amplifiers ● Cascode amplifier ● Amplifier limitations

CHAPTER 6
CATHODE FOLLOWERS

Need for a device having a small input capacitance ● Need for a device having a small internal output impedance ● Polarity of output signal from a cathode follower ● Output impedance ● Voltage gain ● Input capacitance ● Cathode-follower probes ● A method of increasing apparent input resistance ● Bootstrap capacitor

CHAPTER 7
CIRCUITS BASED ON THE CATHODE FOLLOWER

Cathode-coupled amplifiers ● Voltage comparators ● Regulated power supply ● Voltage discriminator for delay-pickoff systems ● Paraphase amplifier ● Variable gain control ● Gain control for push-pull amplifier ● Differential amplifier

CHAPTER 8
DELAY LINES AND DISTRIBUTED AMPLIFIERS

Need for delay lines ● Delay-line characteristics ● Terminations at ends of delay line ● Effect of a discontinuity ● Kinds of delay lines ● Signal-current requirements ● Distributed amplifiers

CHAPTER 9
TIME-BASE GENERATORS

Required horizontal-deflection waveform ● A basic time-base generator ● Gating waveform ● Clamping circuits ● Bootstrap time_base generator ● Basic Miller runup time-base generator ● Practical Miller runup time-base generator ● Miller rundown time-generator ● Phantastron time-base generator

CHAPTER 10
MULTIVIBRATORS

Plate-coupled astable multivibrator ● Detailed operation of plate-coupled astable multivibrator ● Output connections ● Frequency and symmetry controls ● Synchronized operation; frequency division ● Monostable multivibrators ● Plate-coupled monostable multivibrator ● Cathode_coupled (Eccles Jordan) bistable multivibrator ● Schmitt trigger ● Hysteresis in the Schmitt trigger ● Dc levels in the Schmitt trigger ● Free-running form of Schmitt trigger ● Transition time ● Clipping diodes in multivibrators

CHAPTER 11
HORIZONTAL-DEFLECTION SYSTEMS

Block diagram of horizontal-deflection system ● Brief summary of circuit functions ● Detailed operation of horizontal_deflection system ● Single sweep feature ● Triggered single sweeps ● Triggered single sweeps ● Delayed triggers ● TIME BASE B ● B INTENSIFIED BY A ● A DELAYED BY B ● Another Miller-runup time-base system ● Clamp_tube time-base system ● Unblanking circuits

CHAPTER 12
POWER SUPPLIES

Transformers ● Rectifiers ● Rectifier circuits ● Capacitive filter ● Inductive filter ● LC filter ● Low-voltage power supply ● High-voltage power supply