This chapter will cover some of the more popular electronic component devices used in electronics.
The 555 timer is one of the most remarkable integrated circuits ever developed. It comes in a single or dual package and even low power cmos versions exist - ICM7555. Common part numbers are LM555, NE555, LM556, NE556. The 555 timer consists of two voltage comparators, a bi-stable flip flop, a discharge transistor, and a resistor divider network. The 555 timer is ideal for astable free running oscillators as well as the one shot monostable mode.
The 602 mixer is a low-power VHF monolithic double-balanced mixer with input amplifier, on-board oscillator, and voltage regulator. It is intended for high performance, low power communication systems. The guaranteed parameters of the SA602A make this device particularly well suited for cellular radio applications. The mixer is a Gilbert cell multiplier configuration which typically provides 18dB of gain at 45MHz. The oscillator will operate to 200MHz. It can be configured as a crystal oscillator, a tuned tank oscillator, or a buffer for an external LO. For higher frequencies the LO input may be externally driven. The noise figure at 45MHz is typically less than 5dB. The gain, intercept performance, low-power and noise characteristics make the SA602A a superior choice for high-performance battery operated equipment.
615 MIXER FM IF SYSTEM
The SA615 is a high performance monolithic low-power mixer FM IF system incorporating a mixer/oscillator, two limiting intermediate frequency amplifiers, quadrature detector, muting, logarithmic received signal strength indicator (RSSI), and voltage regulator. The SA615 combines the functions of Signetics� SA602 and SA604A, but features a higher mixer input intercept point, higher IF bandwidth (25MHz) and temperature compensated RSSI and limiters permitting higher performance application.
74HC4046 PHASE-LOCKED-LOOP WITH VCO
This is a rather simplistic explanation of a 74HC4046 phase-locked-loop (PLL) with a vco because whole books have been devoted to phase locked loops, offering varying degrees of mathematical complexity. It is not a subject with which you can safely take a casual approach. A vco stands for "voltage controlled oscillator" which has been dealt with earlier in a discrete form. These devices are frequently used in conjunction with digital dividers and frequency synthesisers.
LM3914 DOT-BAR DISPLAY DRIVER
The LM3914 Dot-Bar Display Driveris a monolithic integrated circuit that senses analog voltage levels and drives 10 LEDs, providing a linear analog display. A single pin changes the display from a moving dot to a bar graph. Current drive to the LEDs is regulated and programmable, eliminating the need for resistors. This feature is one that allows operation of the whole LM3914 system from less than 3V.
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Updated 9th April, 2002