The step size of the converter is variable by selection of the high order data bits. The first DAC, A, has a stable reference current supplied via the 10.24 V reference IC and Rl. R2 provides bias cancellation. As shown, only the first 4 MSB inputs are used, giving a step size of 225/256 2.048/16 = 0.127 mA. This current supplies the reference for DAC whose step size is then 0.1275/256 = 0.498 µ. Complementary voltage outputs are available for unipolar output and.....
The input signal is amplified by the transistors. The distorted output is then clipped by the two diodes and the high frequency noise is filtered from the circuit via the 500 pF capacitor..
This decoder will respond to a preselected 4-digit DTMF number. IC7 is a Radio Shack IC device (part #276-1303..
The meter reading is directlyjproportiona! to the logarithm of the input light power. The logarithmic circuit behavior arises from the nonlineardiode pnjunction current/voltage relationship..
The first amplifier circuit is a bird phone. In this circuit, the electret mike (MIC1) is mounted in the neck of a large plastic funnel. The amplifier, built around an MC34119 (which is available from D.C. Electronics, P.O. Box 3203, Scottsdale, AZ 85271-3203; Tel. 800-467-7736, and elsewhere), is then placed outside of the funnel with the pickup facing a nearby bird feeder. The output of the amplifier is then connected to a 16- speaker. The amplifier`s voltage gain is.....
This narrow-stop-band filter can be tuned by the pot to place the notch at any frequency from 45 to 90 Hz. It attenuates power-line hum or other unwanted signals by at least 30 dB..
A 6 V battery can provide 100-150 Vdc center-tapped at a high internal impedance (not dangerous though it can inflict an unpleasant jolt). A 6.3 V transformer is connected ' 'in reverse'' with a transistor used in a Hartley oscillator configuration. The frequency of operation may be controlled by varying the value of the 10 ohm resistor. ..
Applying voltage to the circuit triggers SCR1. With SCRl on, the voltage on the anode of SCR2 rises until SCR2 triggers to commu-tate SCRl. The voltage on the gate of SCRl will swing negative at this time, and only after a positive potential of 0 volt is once again attained, will SCRl retrigger..
The 5AH will trigger when the voltage across the two 0 juF capacitors reaches the breakdown voltage of the lamp. Control can be obtained full off to 95% of the half wave RMS output voltage..
A microphone preamplifier using: om CMOS op amp with its own battery, is small enough to be placed in a case of small microphone. The amplifier operates from a 1.5V battery cathode mercury low supply currents. This preamp will operate at very low power and maintain a reasonable frequency response as well. The TLC251 is operating in low bias (operating at 1.5 V) draws a supply current of only 10 and has a year - frequency response of 3 dB 27 Hz to 4.8 kHz. With 8-pin.....
This circuit includes input guarding, cable bootstrapping, and bias current compensation..
This circuit can detect the positive peaks for signal frequencies higher than 5 MHz. It yields ±1% accuracy for 400 mV to 4 V pk-pk signal amplitudes on sine, square, and triangular waveforms. The Am685 comparator output increases whenever VrN is a greater negative voltage than Vour; the high comparator output, in turn, charges C1 in a positive direction. The CA3140 op amp amplifies the C1 voltage with respect to the ECL-switching-threshold voltage ( -1.3 V).....
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. (Hysteresisre-fers to a difference in the control potentiometer setting at which the lamp turns on and the setting at which the light is extinguished) The additional capacitor C2 in (b) reduces hysteresis by charging to a.....
The preamplifier was designed to signal sources such as low-impedance moving coil cartridges (MC) on turntables high fidelity (and yet still there). The impedance of the amplifier is 100 W. To keep the noise levels low, three double-type transistors MAT03 SSM2220 or linked together to form a differential amplifier. Connecting this amp in front of an operand (OR27) is reduced to very low levels in noise input of the latter. The connections of the bases of the amplifier's.....
The circuit has been designed to accommodate all those who dedicate many hours of their lives by exploring the endless pages of this site. Despite the fact that it consists of only three components (Most were not little!), Is able to provide an indication of whether it actually released the telephone line after a long connection via modem to the network. This can be particularly useful, since there In many cases, the computer claims that the telephone network connection.....
Operational Amplifiers
Computer Systems
Oscilloscopes
Transmitters & Receivers
Sensors & Detectors
ANSI Standards
Low Frequency Amplifiers
Power Amplifiers
Number Systems
Regulated Power Supplies
Analogue Filters
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