NE566

via this auction.

Details:
"Want to know more about the NE566?
Actually, the NE566 can be made to sweep a continuous 1000:1 frequency span with just one fixed timing capacitor. Imagine, continuous linear tuning 20 Hz - 20 KHz or 1 KHz - 1 MHz without switching. A simple op-amp circuit provides the precise voltage control necessary. You set the range with the selection of the timing capacitor.

In our lab tests, we used a 0.047µF timing capacitor to achieve a sweep from 23 Hz to 49.5 KHz. That's an amazing 2150:1 ratio! Waveform symmetry does degrade at the very low end however, so if that is critical, a 500:1 or a 100:1 ratio may be more acceptable.

Even at a 500:1 ratio, only two timing capacitors (one hardwired, one switched) will allow you to sweep across the range of the NE566 from 4 Hz - 2000 Hz and then 2 KHz to the 1000 KHz, FMAX. Frequency is inversely proportional to the capacitance. Use the 0.047µF as a reference. Double it to halve the frequency, halve it to double the frequency, etc. Voltage, tolerances and circuit layout affect results so you cannot predict exactly what capacitor values to use for your desired range. We can only get you started with the schematic. After that, you'll just have to experiment. Not hard at all.

E-Mail us for the schematic.

The NE566 is also found in many of the vintage pinball machines such as Asteroids to make those familiar warbling "UFO" sounds.

Another use for this chip is as a transmitter for a high quality, low distortion Remote FM Speaker System described in AN-146 (132K PDF).

Finally, for you musicians, an excellent book, "Making Music with the 566" by synth guru Thomas Henry shows how to do tricks with the NE566 that even the manufacturer didn't know it could do. We highly recommend it. Google the title to find it.

Typical Applications:
General uses: Communications, Test, Music.
# VCO - Linear / Exponential
# FM Modulation
# FSK Generator
# PLL (Phase Lock Loop)
# Pinball Machine "UFO" Sound
# Clock Generator
# Pulse Width Modulation
# Triangle / Square Wave Function Gen
# Tunable Noise Generator (music)
# 455 KHz IF Sweep Oscillator

If you recognize the utility of '555 timer, you'll be WOW-ed by the versatility of this scarce, Voltage Controlled Oscillator (VCO) / Function Generator.

Only 3 external parts are needed to create a linear voltage-controlled oscillator with both triangle and square wave outputs. [Example below shows Pin 5 with a reference voltage supplied by a resistive divider, but the source can come from anywhere, provided it is within the specification limits.] Add the simple Sinewave Shaper #1 or #2 (Click here) for a complete generator on a budget.

Operating V+ is 10 to 24 VDC. Single or dual supplies. Positive or negative ground.

Apply a variable DC voltage to the '566 control pin (5), and you can easily sweep a full linear 10:1* decade, frequency tuning range with a single timing Resistor / Capacitor pair. Switch in other R1 / C1 combinations to make a very simple, multiple decade function generator up to 1 MHz. That's twice the FMAX of the NE555!

Related application links for the NE566 by Thomas Henry:
ADV-Bass
Tunable Noise Generator (131K PDF)
Sinewave Shaper #3
UD-1 Drum Voice"