Ten kHz VFC uses Charge Pump Variation -  04/09/98 EDN-Design Ideas - (Several circuits included, scroll to find this one) A diode-capacitor charge pump is the starting point for many voltage-to-frequency-converter (VFC] designs.  The circuit in Figure 1 uses a variation on that classic theme to achieve linearity less than 0.05%, micropower operation of approximately 10-�A total draw from a 5 to 36V rail, and bipolar-input capability Design by Stephen Woodward, University of North Carolina, Chapel Hill, NC

Ten-Second Ultra Lower Power Oscillator -  This circuit works much like the classic 555 timer, but draws only about 1.5 microamps from a 3 volt battery.  It is highly stable under varying temperature and supply voltages. . . Circuit by David Johnson P.E.-May, 2000

Testing Dual-Chip Transistor Arrays for VCO/Buffer Amp Combinations & Two-Stage Amplifier Applications 11/28/97  -  App Note  Doc #907) __ California Eastern Laboratories

Tiny Crystal Oscillator using LP2980 -  High-stability gate oscillator uses two, 5-pin SOT packaged devices.   __  Contact:  Charles Wenzel of Wenzel Associates, Inc.

Transconductance Amp Gives Oscillator Reciprocal Response -  17-Apr-03 EDN-Design Ideas - High-side current sensor monitors negative rail - The circuit in Figure 1 is a variation on the familiar integrator/comparator triangle-wave oscillator, which you typically implement with two op amps.  An integrator and a comparator connect in a positive-feedback loop; the comparator drives the integrator and vice versa.  A fixed amount of hysteresis exists in the comparator, producing a triangle wave at the integrator's output Design by Mike Irwin, Shawville, PQ, Canada

Triangle & Square Wave Generator -  Here is a simple triangle/squarewave generator using a common 1458 dual op-amp that can be used from very low frequencies to about 10 kHz.  The time interval for one half cycle is about R*C and the outputs will supply about 10 milliamps of current.  Triangle amplitude can __ Designed by Bill Bowden

Triangle / Square wave generator -  Transistor Q1, a 2N3563, and its associated components form an oscillator circuit that will oscillate if, and only if, a good crystal is connected to the test clips.  The output from the oscillator is then rectified by the 1N4148 signal diode and filtered by C3, a 100pF capacitor.   __ Designed by Izhar Fareed

Triangle to sine converter -  Circuit only __ Designed by Saxons @ Easytreasure.co.uk

Triangle Wave Generator -  This signal generator gives you two waveforms for the price of one: a triangle-wave and a square-wave.  What is the central component of this circuit? The integrator capacitor CI.  Basically we are interested in performing two functions on CI: charge it, discharge it, repeat indefinitely.  During the design process, we ask these (spice design) __ 

Triangle Wave Generator -  This triangle wave generator is made with a trigger Schmitt that converts a triangle wave into a rectangular one used to charge and discharge a capacitor through current sources.  The positive current source T1 provide the charging and T2 the discharging.  The trigger Schmitt is made from OR-EXCL gates IC1a and IC1b.  The __ Designed by Popescu Marian

Triangle waves drive Simple Circuit frequency doubler -  11/23/06 EDN-Design Ideas - Extend a function generator's range, and get a sine wave signal in the bargain Design by Jim McLucas, Longmont, CO

Triangular wave oscillator -  In this page, I introduce the triangular wave oscillator which used the Operational Amplifiers (TL082).  The circuit uses the two OP amplifiers.  The OP of the one works as "the Schmitt circuit".  The other OP works as "the integration circuit".  At the circuit diagram above, IC (1/2) is the Schmitt circuit and IC (2/2) is the integration circuit __ Designed by Seiichi Inoue

Tritium - Type 3 (charge rate controlled) Solar Engines

Turn a Set/Reset Latch Into an Astable/Monostable Multivibrator -  3-Sep-09 EDN-Design Ideas - Use latches with either active-high or active-low inputs Design by Luca Bruno, ITIS Hensemberger Monza, Lissone, Italy

Twin-T Audio Sine Wave Oscillator -  This circuit produces a clean sine wave signal ideal for audio testing, or wherever a good-quality sine voltage source is required.  It uses only one integrated circuit which is a common dual operational amplifier, the Texas Instruments TL072CP.  The values shown provide an output frequency of about 1000 Hertz.  This frequency may be varied over a wide range, using the formula shown in the schematic.  For most audio frequencies, the oscillation rate is almost exclusively determined by __ Designed by Arthur Harrison

Twin-T oscillator -  This circuit produces an extremely low distortion sine wave, in spite of the non-linear devices used for amplitude limiting (D1 and D2).  The reason is first that distortion (harmonics) is fed to the minus input of the OpAmp with far less loss than to the __ Designed by Andrew R. Morris

Two Stage Chaotic Colpitts Oscillator for the UHF range -  Chaos in the Colpitts oscillator was first reported at the kilohertz frequencies [1].  Later the circuit was investigated in the high frequency (HF: 3 to 30 MHz) range [2, 3].  Chaotic oscillations were demonstrated.  __ 

Two Tone Audio Oscillator -  Circuit Only __ Contact Peter Parker VK3YE

Two Transistor Wein Bridge Oscillator -  Scroll Down to find this circuit.  Here is a two-transistor Wien bridge oscillator using an ordinary night-light bulb for stabilization.  The output is about 6 volts p-p and can drive fixed loads as low as 2 or 3 thousand ohms without additional buffering.  A 10 k amplitude potentiometer.   __  Contact:  Charles Wenzel of Wenzel Associates, Inc.

Ultra Low Current Oscillator -  Here is a challenge.  Design an astable oscillator which draws only a few nanoamps of current from a +3v supply.  I gave this some thought and came up with the circuit below.  I used some pretty standard parts except for three surface mounted 1000M resistors I had on hand.  The oscillator frequency measured a low 1Hz frequency and the average current was a very low 3 nanoamps.  If I had some higher resistors values handy, I think I could have gotten the current down below one nanoamp. . . Circuit by David A. Johnson P.E.-March, 2009

Ultra Low Current Oscillator #4 -  The circuit below was inspired by a programmable unjunction transistor (PUJT) circuit sent to me by Karl Isbrecht.  In Karl’s circuit, the unijunction circuit made click sounds in a speaker and consumed very little power.  His circuit reminded me that a PU. . . Circuit by David Johnson P.E.-January, 2010

Ultra Low Power 32Khz Crystal Oscillator -  I have used this circuit many times when I needed a low frequency reference, which did not draw much power.  With the components show, the current from a 3v battery is less than 1.2 microamps . . . Hobby Circuit designed by David Johnson P.E.-December, 2004

Ultra Low Power Astable Multivibrator -  Taking advantage of some new voltage comparators, this circuit can produce a nice square wave signal while drawing only 1.6 micro amps.  With the inclusion of a diode, the circuit can also produce short pulses instead of a square wave signal. . . Circuit by Dave Johnson P.E.-December, 2004

Ultra Low Voltage Crystal Oscillator using Active Loads -  Circuit Ideas for Designers App Note__ Advanced Linear Devices, Inc

Ultra Low Voltage Micropower Crystal Oscillator -  Circuit Ideas for Designers App Note__ Advanced Linear Devices, Inc

Ultra Low Voltage Nanopower LC Colpitts Oscillator -  Circuit Ideas for Designers App Note__ Advanced Linear Devices, Inc

Ultra Lower Power Oscillator -  This circuit works much like the classic 555 timer, but draws only about 1.5 microamps from a 3 volt battery.  It is highly stable under varying temperature and supply voltages. . . Circuit by David A. Johnson P.E.-May, 2000

Ultra Pure 125kHz Sine Wave Signal Source -  For some RFID systems operating at 125KHz, a very low distortion signal source reference is needed.  The circuit shown on this page produces a 10-volt peak-to-peak signal into a 50-ohm load, with a distortion of only 0.01%. . . Circuit by Dave Johnson P.E.-February, 2002

Universal Watchdog Fully Controls µ Preset -  05/25/95 EDN-Design Ideas - Many µPs contain internal watchdog timers, and you may wonder why you need another stand-alone circuit.  Unfortunately, more highly integrated functions have preset parameters that you may want to change.  Also, internal watchdogs are generally a simple combination of a flip-flop and a timer.  If the program does not start properly on the first try, the timer is of no use because the program never turns on the watchdog.  This watchdog catches exactly this condition Design by Terje Kvinge, Nera AS, Kokstad, Norway

Use of the CMOS Unbuffered Inverter in Oscillator -  Texas Instrument Application ReportSZZA043 January 2004 __ Designed by Moshiul Haque and Ernest Cox

Use PSpice for behavioral Modeling of VCOs -  12-Dec-02 EDN-Design Ideas - PSpice, a member of the Spice family for PC users, is becoming a standard tool for analog and mixed analog-digital simulation.  Many analog designers are familiar with the software of Design Center, Design Lab, and OrCad (www.orcad.com] PSpice and use the software in their everyday lives.  This design idea should be helpful to those who design and simulate PLL systems at a behavioral level Design by Dobromir Dobrev, Jet Electronics, Sofia, Bulgaria

Using the LTC6900 Low Power SOT-23 Oscillator as a VCO -  DN293 Design Notes__ Linear Technology/Analog Devices

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