Make a simple ramp generator for stepper motors:  04/04/02 EDN Design Ideas  /  (added 1/05)  Stepper motors are synchronous motors that step at the pulse rate of the driving signal. For the motor to move quickly, the stepping rate must be fast. However, because of motor and load inertia, the motor often cannot go from 0 rpm to the desired number of revolutions per minute in one step. Therefore, most stepper motors receive their drive from a pulse chain that starts out slowly and ... ...

Microphone Circuit Test Oscillator:  440 Hz Tone generator for testing XLR microph1-lines (Electronic circuit added 5/02)

Micro-power Band-pass Network:  Circuit Ideas for Designers - Application Notes - Advanced Linear Devices, Inc.  (Circuit / schematic design added 6/06)

MonoStable Flip Flops (One Shot):  (Electronic Schematic / circuit added 4/02)

NanoPower LC (Colpitts) Oscillator Circuits:  Circuit Ideas for Designers - Application Notes - Advanced Linear Devices, Inc.  (Circuit / schematic design added 6/06)

Negatrons Enrich Filter Oscillator Designs:  07/21/94 EDN-Design Ideas  / (Electronic Circuit diagram added 03/03) The latest wave of high-performance op amps allows you to incorporate "negatrons" (synthesized negative resistors) into your oscillators and filters. Fig 1 shows the universal filter/oscillator circuit based on a simulated lossy inductor and a negative resistance, which compensates the lossy inductor. Note that the circuit has no physical inductors. The performance of this circuit is very predictable and repeatable. Op-amp IC2 and its associated components form a gyrator that simulates the inductance LEQ=C2R4R5. Paralleling LEQ with C1 forms a parallel-resonant LC tank circuit. Op amp IC1 and its associated components form the negatron that simulates a negative resistance, -(R1R3)/R2....  

NTSC Test Signal Generator:  An accurate test signal generator for television calibration and measurements.  (Circuit / schematic design added 6/06)

One IC 2 Tones Siren Double Tone Police Sound Single Tone Old Ambulance Sound:  This circuit is intended for children fun, and is suitable to be installed on bicycles, battery powered cars and motorcycles, but also in models and other games. With SW1 positioned as shown in the circuit diagram it reproduces the typical dual tone sound of Police or Fire-brigade cars, by the oscillation of IC1A and IC1B gates. (Circuit added 9/04)

One Second Time Base from Crystal Oscillator:  (Electronic circuit added 7/03)

OpAmp Oscillators Simplify RF Designs:  10/10/96 EDN-Design Ideas / (Electronic Circuit diagram added 03/03)

Oscillator Circuit Types:  (Electronic circuit design added 02/05)

Oscillator Lowers Distortion and Phase Noise:  08/18/94 EDN-Design Ideas / (Electronic Circuit diagram added 03/03) In addition to its normal role of controlling oscillation frequency, the crystal in Fig 1 also acts as a high-Q, self-tuned output filter, which rejects the noise and harmonics of its input voltage, VB. The result is a clean output-frequency spectrum. With an output frequency of 10.7 MHz, second harmonic distortion is -76 dBc, and third-harmonic distortion is -72 dBc. Other harmonics are less than 80 dBc, and output power is +7 dBm at 50 Ohms. C1 and R4 counterbalance the undesirable effects of the parallel capacitance CP of the crystal, which represents a side path through which the highest harmonics of VB can reach the output. ...  

Oscillator turns on Instantly off Synchronously:  05/23/96 EDN-Design Ideas / (Electronic Circuit diagram added 03/03)

Pager Testing Using the 8648A with an Internal Pager Encoder, Option 1EP:  Agilent Application Note   (Circuit / schematic design added 6/06)

PIC Controlled DDS VFO 0 to 6 MHz:  (Electronic Schematic / circuit added 4/02)

Pierce Crystal Oscillator Design:  The Pierce oscillator ... is essentially a common emitter amplifier with a tuned circuit for a collector load and a quartz crystal as a feedback element. In order to determine whether the Barkhausen criteria is satisfied, loop gain must be determined at the frequency of oscillation. This is accomplished by drawing the AC equivalent circuit of the Pierce Oscillator... (Electronic circuit design added 02/05)

Pierce-gate Oscillator Crystal load calculator:  RF Design - Design Tips, July 2004 (Electronic circuit design added 02/05)

Positive Feedback:  The use of positive feedback is useful for producing oscillators. The condition for positive feedback is that a portion of the output is combined in phase with the input. For an amplifer with positive feedback the gain is given by the expression below. (Electronic circuit design added 02/05)

Precision Waveform Converter uses Sawtooth Wave:  03/01/96 EDN-Design Ideas / (added 03/03)

Programmable Oscillator uses digital potentiometers:  03/07/02 EDN Design Ideas  /  (added 1/05)  Digital potentiometers are versatile devices; you can use them in many filtering and waveform-generation applications. This Design Idea describes an oscillator in which setting the resistance of two digital potentiometers independently programs the oscillation amplitude and frequency. Figure 1 shows a typical diode-stabilized Wien-bridge oscillator that generates accurate sine waves fro... ...

Programmable Ramp Generator has 14 Bit Linearity:  09/12/96 EDN-Design Ideas / (Electronic circuit added 5/02)   This linear ramp generator uses a DAC, a transistor array, MOSFET switches, and current-steering techniques to achieve 14-bit linearity (Figure 1). The output current of IC1, a DAC-10, is a product of the digital code and the reference-current input, where IO=(code/1024)×2IR. IR is the output of reference IC6 divided by R1. Q1A, Q1B, and Q1C of the CA3096 transistor array form the current sink and share the IO current from the DAC. Q1A simply scales the current by shunting one-third of IO. The pnp transistors of the same array, Q1D and Q1E, mirror the sink current to form a current source of the same magnitude. The slope input signal drives optocoupler IC4, which isolates....

Pulse Stretcher Increases ECL Gate Gains:  01/20/94 EDN-Design Ideas / (Electronic Circuit diagram added 03/03) stretches the output pulses of an ECL comparator by operating the ECL line receivers with unusually large pulldown resistors to the -15V supply. The large load resistance maximizes the gains of the emitter-follower output stages and speeds up the rising edges. At the same Time, the low pulldown current, together with the input and wiring capacitances, slows the falling edges. These actions stretch the positive pulses by approximately2 nsec/stage.

Quad Astable Mode Operation (Free Running Oscillator):  Circuit Ideas for Designers - Application Notes - Advanced Linear Devices, Inc.  (Circuit / schematic design added 6/06)

Reflections: Computations and Waveforms:  National Semiconductor - Application Note   (added 2/06)

Resonant Frequency of a Colpitts Oscillator:  (Electronic circuit design added 02/05)

Resonator BFO Circuit:  This circuit was used to stop all the BFO drift. The circuit is extremely stable. Turn the receiver off, and then on at any time and temperature, the BFO frequency is exactly the same. (Electronic circuit design added 02/05)

RF Oscillator uses Current feedback op amp:  10/03/02 EDN Design Ideas  /  (added 1/05)  A current-feedback amplifier is a well-known component with many uses. Its basic block diagram shows that its input stage is a voltage follower—in practice, a symmetrical emitter follower (Figure 1). The configuration samples the output current, converts it to voltage across a large impedance, and amplifies it to the output using a high-power, low-output-impedance amplifier....

RF Signal Generator:  (added 2/05)

Rounding Off' a Square Wave:  (Electronic circuit added 7/03)