Page 229 - Troubleshooting Analog Circuits

216 index

timers,46, 120-121, 134, 141 cellular layout, 82 secondary breakdown possible
CMOS timers, 120 current-hogging, 82.87-88 at high voltage, 87
leaky capacitors, 120 beta, 77-79.105 gate voltage-max. ratings, 88
LM555/LMC555,120 degradation, 77-78 oscillations, 87,88
logic diagram /flow chart, 121 matching, 79 unprotected gates
slow oscillators, 120 too high, 78-79 used in op amps, 8 1
trimming oscillators, 120 biassing, 77-79 used in picoammeters, femtoam-
tools, 3, 12, 14,23,58,70, 126, 138, bond wires, 9.78 meters 8 1,88
169, 173, 177,203,2&207. capacitances, 81,145 transistors, structures, 84-85,85,86
See also equipment collector connections, 50,80,85,86 epi-base, 8445.85
tools, inadequate, 14 Darlington, 58.79 planar, 84.85
“touch-in” technique. See under trouble- delicate discrete transistors, 78 single-diffused (obsolete) 8485.86
shooting techniques Early voltage, 79 trim-pots. See under resistors,
transconductance, 79,192 ESD damage, 78.81 adjustable
transformers, 18-19,26,35-39, 110- gender confusion, 77, 176 troubleshooting techniques (specific
111,137-138,140, 155 hrb, 79 techniques)
back-to-back transformers. See under input overdrive, 77-78,104,115, add-on, 47-48
isolation transformers 1 59-1 6 1 ask-your-buddy, 12
bifilar windings, 38 installed with incorrect orientation, beer-check, 4.4
comparison tests, 35.37 77, 186 “gimmick capacitors, 20
cup-core, 35 light-sensitive, 74, 156 help-your-buddy, 12
E-I cores, 35 melting, 77.82.87 “Paralysis by Analysis,” 6
ferrite, 35 negative tempco of VBE, 78 planning, 5,12
insulation, 37 oscillations, 84,87, 108,109,118 “spring-loading” components, 48
isolation, 18-19.20 output overload, 77, 105 substitution, 18,43,47
inter-winding capacitance, 36.38 secondary breakdown, 81-82.87 “touch-in” technique, 47.48, 176
leakage inductance, 35.36 sharing (ballasting) resistors. See “Twiddle-box,” 18
magnetic flux, 35.38-39 ballasting TV receivers. See television receivers
power transformers. 34,37,39, SOA (safe operating area), 81-82, two-layer metal, 7
110-111 84-85 “Typicals” or non-guaranteed character-
primary inductance, 35.36 FBSOA (forward-biassed safe istics, 81.96.98, 104-105,
rod core, 34.39 operating area), 88 199
saturation and overdrive, 35, 110-1 11 thermal runaway, 82,
secondary inductance, 35.36 thermal limiter circuits, 82, UA741 (pA741). 77. See also LM741
similarity to inductors, common 105-106.117
features, 37 turn-off circuits, 82, 159-161 VOS vs. temperature gradients, 78
test conditions, 35-36 transconductance (gm), 71,79,192 vacuum tubes, xi, 22,40,42,88, 147,
toroidal core, 37,39, 11 1 function of temperature, 79 188
turns ratios, 35-37.36 function of collector current, 79 vapox, 7
twisted pairs, 38 VBE, 78 variable capacitors. See capacitors,
variable, 40. See also under Variac tempco of VBE, 78 adjustable
winding conventions matching of VBE, 78.86 variable resistors. See resistors, ad-
transistors, bipolar, 77-79,81-88,104, voltage gain, 71.78 justable
108,109, 115, 118,176, 177, predictions, formula, 79 Variac, 19
180,184,204,206, transistors, JFETs, 79-80. See also Varoom, 172
2N918.78 transistors, MOSFETs VFC. See under voltage-to-frequency
2N930.66 2N4117A. 2N4118A. 2N4119A. 66 converters
2N2222.84 2N5485.2N5486.16 video display terminal, 155
2N2369.78 problems with JFETs: “virtual ground,” 97
2N3055.84 excess gate current, 80 Vishay, 155
2N3055H, 84 gate connections, 80 voltage gain. See under operational
2N377 1.84.85 low transconductance, 79 amplifiers, or transistors
2N3904,66,69,73,77,84,109,196 Vgs match, 79 voltage references
2N4275,78 V,, stability and tempco, 79-80 band-gap type, 71,135,154,206-207
2N5039.84 transistors, MOSFETs, 81.87-88 broadband noise, 135, 180
data sheet curves, 82 3N160.81 Zener-based, 71, 135. See also Zener
photo transistors, 74 IRF511,164 diodes
power transistors, 72.81-86, 138, analog switches, 81 buried zeners, 71, 135, 147
140,159-161,167-168 CMOS digital ICs. See under digital long-term stability, 29.71, 135. 147
used as a diode, 66-67.69-70, 167, ICs voltage regulator ICs (linear), 130,177,
196 problems with MOSFETs: 81,87-88 181, 183,185,177-181,
bipolar transistor problems: DMOS FETS, 88 191-193. See also switch-
alleged unreliability per MIL- parasitic bipolar transistor, 88 mode regulators
HDBK 217.77 ESD tolerance. 81.88 adjustable, 152, 153. 177-181.177,
base-emitter breakdowdzenering, ESD precautions, 81.88 178,191-193
77,79. 159-161 unreliability after ESD, 8 1 heat-sinks needed, 135
high-current beta not degraded, excessive bandwidth, 87-88 output capacitor needed for negative
77-78 freedom from secondary break- regulators, 135-136
ballasting (emitter ballasting), 82.83 down, 87 output impedance, 136,191-193