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An omnidirectional electret microphone can be used to pick up the sound and convert it into an electrical signal. The output of the microphone is fed along two paths. In the first path, the signal is sent to the inverting input at pin 6. In the second path,....
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Large LCD devices of 1 or more exhibit a large driving capacitance to the driver circuits. To solve this problem, the drive circuit shown (see the figure) introduces a buffer amplifier for each of the three common lines. Each amplifier can be programmed....
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The two lamp-dimmer circuits differ in that (a) employs a single-time-constant trigger network and (b) uses a double-time-constant trigger circuit that reduces hysteresis effects and thereby extends the effective range of the light-control potentiometer.....
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The zener provides a constant voltage of 20 V to unijunction transistor Ql, except at the end of each half-cycle of the input when the line voltage drops to zero. Initially, the voltage across capacitor Cl is zero and capacitor C2 cannot charge to trigger....
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This very special mains-operated dimmer for domestic or industrial lights is not available in proprietary form: it ena..
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Lamp II is a household lamp. When the switch is in the center position, the lamp is operated on half-wave rectified ac; the ef..
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Here"s an interesting mixer circuit. With it you can effectively combine signals from audio to high-fre-quency RF. Als..
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As shown, a 555 timer (Ul) is configured as an astable multivibrator (oscillator) with a 400:1 duty cyc..
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A very simple motion transducer can be constructed using the circuit shown. The output is biased to one-half the supply voltage. This requires special interface circuitry for the signal readout. One simple method is to use a zero center meter in a bridge....
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The circuit consists of four stages of active bandpass filtering provided by two type-µ integrated-circuit dual op amps and includes a simple threshold detector (diodes Dl and D2) between stages 2 and 3 to reduce low-level background noise. Each of the four....
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The Quad op amp MC4301 is used to configure a filter that will notch out a given frequency and produce that notched-out frequency at the BP terminal, useful in communications or measurement setups. ..
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A differential amplifier makes an excellent audio clipper and can provide precise, symmetrical clipping. The circuit shown commences clipping at an input of 100 mV. The output commences clipping at ±3 V. Matching Q7 and Q2 is necessary for good symmetrical....
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Component value sensitivityis extremely critical, as are temperature coefficients and matching of the components. Best performance is attained when perfectly matched components are used and when the gain of the amplifier is unity..
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A shows a twin-T network connected to an LM102 to form a high Q, 60 Hz notch filter. The junction of R3 and C3, which is normally connected to ground, is bootstrapped to the output of the follower..
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This narrowband filter using the 741 operational amplifier can provide up to 60 dB of rejection. With resistors equal to 100 K and capacitors equal to 320 pF, the circuit will reject 50 Hz. Frequencies within the range 1 Hz to 10 kHz may be rejected by....
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This nonlinear, passive filter circuit rejects ripple (or unwanted but fairly steady-voltage) without appreciably affecting the rise time of a signal. The circuit works best when the signal level is considerably lower than the unwanted ripple, provided the....
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The first stage is a simple buffer used to isolate the signal source from the attenuator stages to follow. Each of the subsequent stages is preceded by a voltage divider formed by two resistors and CMOS switch. Provided that the CMOS switch for each stage....
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This circuit performs the function of dividing the input signal by a selected constant (1, 2, 4, 8, etc.). While T, Z, or L sections could be used in the input attenuator, this is not necessary since the amplifier loading is negligible and a constant input....
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Automatic gain control is a very useful feature in a number of audio amplifier circuits: tape recorders, telephone speaker phones, communication systems and PA systems. This circuit consists of a HA-5144 quad op amp and a FET transistor used as a....
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This is a second-order, low-pass filter with programmable cutoff frequency. This circuit should be driven from a low-source impedance since there are paths from the output to the input through the unselected networks. Virtually any filter function which....
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This universal filter offers low-pass, high-pass, bandpass, band elimination, and all-pass functions. The Biquad consists of two successive integration stages followed by an inverting stage. The entire group has a feedback loop from the front to the....
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The control voltage Vc easily sets the cutoff frequency w0 of this state-variable filter to any desired value, from about 1.7 MHz up to 5 MHz, with a BB 204 varicap and R = 100 KO. Vc can range from 0 to 28 V. This range changes the capacitance of the....
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This circuit filters noise, such as glitches and contact bounce, from digital signals. You can easily adjust the circuit for a wide range of noise frequencies. The circuit"s output changes state only if the input differs from the output long enough for....
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A generalized circuit diagram of the two-pole state-variable active filter is shown. The state-variable filter can be inverting or noninverting and can simultaneously provide three outputs: low-pass, bandpass, and high-pass. A notch filter can be realized....
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This circuit is fed from the earphone jack of your receiver and goes to limiter control R6 and is then amplified by Ql: a common-emitter stage that has a voltage gain of only about 10, because of the negative feedback introduced by R3. The output of Ql is....
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HA-5190 is rated for ±5 V output swing, and saturates at ±7 V. As with most op amps, recovery from output saturation is slow compared to the amplifier"s normal response time. Some form of limiting, either of the input signal or in the feedback path,....
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The circuit allows you to eliminate the vocal portion of an audio signal, while leaving the instru mental portion. The circuit mixes two channels that must be 180° out of phase, so the signals that form the center-stereo image is canceled out. Those....
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This filter is used to reject or block a frequency or band of frequencies. These filters are often designed into audio and instrumentation systems to eliminate a single frequency, such as 60Hz. Commercial grade components with 5%-10% tolerance produce a....
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This circuit shows a twin-T network connected to an LMl02 to fonn a high-Q, 60-Hz notch filter. The junction of R3 and C3 which is normally connected to ground, is bootstrapped to the output of the follower. Because the output of the follower is a very low....
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Otherwise properly mixed sounds often suffer from a predominant solo voice (which might, of course, be the intention). If ..
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This circuit uses two balanced modulators to produce a DSB signal and then reinsert the carrier, except t..
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This 2-band compressor splits the audio into high and low frequencies and allows independent adjustmen..
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Signetics" type NE575 compander IC is intended primarily for use with battery power supplies of 3 to 7 V (max. 8 V). It..
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By introducing an extra transmission zero to the stopband of a low-pass filter, a sharp roll-off c..
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Many record players unfortunately exhibit two undesired side effects: rumble (noise caused by the motor and the turntable) and other low-frequency spurious signals. The active high-pass Chebyshev filter presented here was designed to suppress those noises.....
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One of the difficulties in the design of higher-order tunable bandpass filters is achieving correct tracking of the..
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Two dual-biquad filter chips and some external components form a multipurpose filter to reconstru..
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A standard dual integrator filter can be constructed using a few CA3080s. By varying LABC, the reso..
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The NE604"s signal-strength indicator section is used, based on an internal logarithmic converter. This enables a linear ..
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This frequency/voltage converter enables calibrations of cassette-deck speed. It records a steady 1-kHz ton..
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Examples of RF and audio ANL circuits. Positive and negative clipping occurs in both circuits. The circuit at A i..
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This circuit detects the presence of audio (voice) on the output of a scanner. If the scanner stops on a "dead carrie..
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The classic state-variable (two-integrator) filter (see Fig. A) is famous for its insensitivity to device parameter tolerances, as well as its ability to provide three simultaneous separate outputs: high pass, bandpass, and low pass. These advantages often....
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This circuit is a variable audio bandpass filter that has a low cutoff variable from about 25 Hz to 700 Hz and a high cutoff variable from 2.5 kHz to over 20 kHz. Rolloff is 12 dB/octave on both high and low ends...
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This variable-frequency, audio bandpass filter is built around two 741 op amps that are connected in cascade. Two 741 op amps are configured as identical RC active filters and are connected in cascade for better selectivity. The filter`s tuning range is....
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The LTC1063 is the first monolithic low-pass filter that simultaneously offers outstanding dc and ac performance. It features internal or external clock tunability, cutoff frequencies up to 50 kHz, 1-mV typical output dc offset, and a dynamic range in....
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A complete schematic diagram of the voice disguiser is shown. Microphone MIC1 picks up the voice signal and feeds it to an audio amplifier, consisting of Ql and Q2, and a few support components. The amplifier has a low-pass gain response that limits the....
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Low-frequency signals produced by transducers, measurement equipment, or data loggers often appear like the first waveform in the figure. The circuit shown operates as a tracking sample-hold, and the transients are replaced in the output by the stored value....
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When the comparator`s output changes its state from low to high, the rising edge of the output pulse, differentiated by the Cl/Rl chain, opens Ql. This blocks comparator via its strobing input and sustains its output in the state for a period of time,....
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The noise limiter circuit has a preamplifier clipper, and a switchable audio bandpass filter. Audio levels in the 5- to 50-mV range are amplified in a preamp to several volts p-p, fed to a clipper, voice band filter, ..
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The precision input characteristics of the HA-5147 help simplify system error budgets, while its speed and drive capabilities provide fast charging of the multiplexer"s output capacitance. This speed eliminates an increased multiplexer acquisition time,....
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The noninverting amplifier has a gain of R2/R3 (1 in this case) and produces a voltage of V,"" during a positive excursion of Vin with respect to ground. The inverting amplifier accommodates the negative excursions of V..; its gain is given by -R6/R7,....
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In intrinsically safe applications, it is sometimes necessary to separate sections of circuitry by resistors which limit current under fault conditions. The circuit shown provides an accurate analogue output with effectively zero output impedance, despite....
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This simple circuit is a gain-of-1000 inverting amplifier. It will amplify submillivolt signals up to signal levels suitable for further processing. In almost all system applications, it is best to use as OUTPUT much gain as possible in the MAX420, thus....
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A composite configuration greatly reduces de errors without compromising the high-speed, wideband characteristics of HA-2539. The HA-2540 could also be used, but with slightly lower speeds and bandwidth response. The HA-2539 amplifies signals above 40 kHz....
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The modified inverting amplifier uses an active clamp to limit the output swing with precision. Allowance must be made for the V8E of the transistors. The swing is limited by the base-emitter breakdown of the transistors. ..
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The NE592 is connected in conjunction with a MC1496 balanced modulator to form an excellent automatic gain control system. The signal is fed to the signal input of the MC1496 and re-coupled to the NE592. Unbalancing the carrier input of the MC1496 causes....
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The LT1012 corrects de errors in the booster stage, and does not set high-frequency signals. Fast signals are fed directly to the stage via Q5 and the 0.01-uF coupling capacitors. De and low-frequency signals drive the stage via the op-amp"s output. The....
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This amplifier functions over a wide range of gains, typically 1-10. It combines the LT1010 and a fast discrete stage with an LT1008 based de stabilizing loop. Q1 and Q2 form a differential stage which single-ends into the LT1010. The circuit delivers 1 V....
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The proliferation of industrial and computerized equipment containing programmable memory has increased the need for reliable recording media. The magnetic tape medium is presently one of the most widely used methods. The primary component of any magnetic....
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Adding two passive components to a standard photodiode amplifier reduces noise. Without the modification, the shunt capacitance of the photodiode reacting with the relatively large feedback resistor of the transimpedance (current-to-voltage) amplifier,....
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This unity-gain follower amplifier has a CMOS p-channel input, an npn second-gain stage, and a CMOS inverter output. The IC building blocks are two CA3600E"s (CMOS transistor pairs) and a CA3046 npn transistor array. A zener-regulated leg provides bias for....
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This circuit measures the power -supply current of a circuit without really having a currentshunt resistor: R1 is only 3 em of #20 gauge copper wire. A length of the power distribution wiring can be used for Rl. ..
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The traditional restnct1on of constant gainbandwidth products for a voltage amplifier can be overcome by employing feedback around a current amplifier. Two current mirrors, constructed from transistors in a CA3096AE array, effectively turn the LF351 op amp....
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This circuit has an overall gain of 320. More gain can easily be obtained by lowering the value of R2. Untrimmed Vas is 10 11V. and Vas tempco is less· than O.lJIV/°C. ..
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LTC1043 and LT1013 dual op amps are used to create a dual instrumentation amplifier using just two packages. A single DPDT section converts the differential input to a ground-referred single-ended signal at the LT1013"s input. With the input switches....
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Has an input resistance of 1-MO, a bandwidth from de to about 35 MHz, and a gain of 10 times. Lowfrequency gain is provided by a CA3130 BiMOS op amp operated as a single-supply amplifier. High-frequency gain is provided by a 40673 dual-gate MOSFET. ..
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This circuit relies on extremely high input impedance for effective operation. The HA-5180 with its JFET input stage, performs well as a preamplifier. The standard three amplifier configuration is used with very close matching of the resistor ratios....
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The MAX420 is operated at a gain of 191 to convert the 52 p.VI o C output of the type J thermocouple to a 10 mV/°C signal. The -2.2 mV/°C tempco of the 2N3904 is added into the summing junction with a gain of 42.2 to provide cold-junction....
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This has a stable trigger 100 m V sensitivity at 50 MHz. The FETs comprise a simple high-speed buffer and the LT1016 compares the buffer"s output to the potential at tbe trigger level potentiometer, which can be of either polarity. The 10-KO resistor....
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This is a single gain-of-100 amplifier with a gain-bandwidth product of 20 MHz! The primary limitation in the performance is the low slew rate (0.3 VIJ1s) imposed by IoH charging CcoMP· The effects of slew rate and compensation are shown. A lower gain....
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Ql and Q2 constitute a simple, high-speed FET input buffer.·Ql functions as a source follower, with the Q2 current-source load setting the drain-source channel current. The LT1010 buffer provides output drive capability for cables or whatever load is....
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Ql and Q2 constitute a simple, high-speed FET input buffer. Ql functions as a source follower, with the Q2 current source load setting the drain-source channel current. The LT1010 buffer provides output drive capability for cables or whatever load is....
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Often a circuit will be called upon to perform several functions. In these situations, the variable gain configuration of this circuit could be quite useful. This programmable gain stage depends on CMOS analog switches to alter the amount of feedback,....
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Adding an unity-gain buffer to your analog circuit can increase its precision. For example, by itself, the op a..
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This power booster functions as a high-efficiency "power multiplexer" or, if you supply an external signal-source, ..
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This op amp offers a straightforward method of developing a single-polarity stable voltage source (see the figure). TVansi..
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This circuit produces 5- to 25-V output to drive a VCO from a standard ± 15-V supply system. R7 and CI supply fr..
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This circuit has high output only when all three inputs are high. The noninverting-input current, when all thre..
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This circuit has proved to be an effective video buffer and will easily drive a 75- load to 1.5-V p-p output. BW is better than 20 MHz and there is less than 0.05-V dc offset, which is the difference in VBE of Ql and Q2...
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By adjusting one potentiometer, this circuit`s output can be varied from a positive-going version of the input signal, smoothly through zero output, then to a negative-going version of the input (see the figure). If the input signal is a positive pulse of,....
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An ultra-low-noise, low-distortion op ampthe AD797is combined with the ADS 11 op amp, which offers a high bandwidth and a 100-mA output drive capability. The composite-amplifier circuit serves quite well when driving high resolution ADC`s and ATE systems.....
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This circuit will run from a single 5 V power supply. The LTC1043 switched-capacitor instrumentation building block provides a differential-to-single-ended transition using a flying-capacitor technique. Cl alternately samples the differential input signal....
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The circuit uses the LTC1043 in a variable gain amplifier which features continuously variable gain, gain stability of 20 ppm/°C, and single-ended or differential inputs. The circuit uses two separate LTC1043s. LTC1043B is continuously clocked by a....
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The DG419looks into the high input impedance of the op amp, so the effects of Rvs(o"l are negligible. The DG441 is also connected in series with RIN and is not included in the feedback dividers, thus contributing negligibleThe usual method for using a current-feedback amplifier to drive a capacitive load isolates the loa..The circuit is designed to drive an external load. A fault condition in the external load circuit could feed excessive current or voltage back into the line drive circuit. If excessive voltage appears from the load, the two zener diodes will clamp that....This circuit offers the best of both worlds. It can be combined with a low input offset voltage and drift without degrading the overall system`s dynamic performance. Compared to a standalone FET input operational amplifier, the composite amplifier circuit....The timer includes an oscillator and a counter in an integrated circuit. The timing interval equals the oscillator period multiplied by the number of cycles to be counted. The oscillator frequency depends upon resistor RS and capacitor CX. The number of....The µA2240 may easily be configured as a programmable voltage controlled timer with a minimum number of external components. The modulation input (pin 12), which allows external adjustment of the input threshold level. A variable voltage is applied from the....Switch programmable on/off or interval timer, has three relay-switched outputs. Output one is active for the duration of time 1, output two is active for the duration of time 2, and output three is active for the duration of both one and two. Timing data is....Many applications, such as computers, require signals for initializing conditions during start-up. Other applications such as test equipment require activation of test signals in sequence. SE555/NE555 circuits may be connected to provide such sequential....By utilizing both halves of a dual timer it is possible to obtain sequential timing. By connecting the output of the first half to the input of the second half via a 01 µF coupling capacitor sequential timing may be obtained. Delay ti is determined by the....The timer interval starts when power is applied to circuit and terminates when voltage is applied to load. 2N2646 is used in oscillator which pulses base 2 of D5K..By utilizing both halves of the dual timer it is possible to obtain sequential timing. By connecting the output of the first half to the input of the second half via a 01 µ-F coupling capacitor, sequential timing may be obtained. Delay ti is determined by....Time delays from 0 milliseconds to over three minutes are possible with this circuit without using a tantalum or electrolytic capacitor. The timing interval is initiated by applying power to the circuit. At the end of the timing interval, which is determined....The ac line-operated on/off controller is a simple, reliable solid-state alternative to a motive driven cam switch. Time 1 and time 2 are programmed by diodes to be 8 hours and 20 hours respectively. The TIM1 output is buffered by a transistor to supply gate....Press SI. The 100 µF electrolytic capacitor rapidly charges up at about 0 V. The transistor will be forward biased, and collector current will flow operating the relay. Release SI. The capacitor will begin to discharge via the 33 K resistor at the base of....Rl and R2 hold the inverting input at half supply voltage. R4 applies feedback to increase the input impedance at pin 3. Pin 3, the nonin-verting input, is connected to the junction of R3 and C. After the switch is opened, C charges via R3. When the....The timer can be used wherever time periods of up to seven minutes duration are needed. To turn on just touch the turn-on plate, and after the selected time has elapsed, an alarm will sound for a short period, then automatically turn off. The turn-on touch....