Circuits & Schematics - Oscillators

In Part 1, we saw how to make an oscillator whose pitch, as opposed to frequency, can be made proportional to a control voltage. In this second part, we’ll look at some alternative ways of arranging things for other possible applications. To ...

The recent Design Idea “Getting an audio signal with a THD 0.0002% made easy” [ 1 ] discloses a low THD sine generator which led me to dust off a design that I had published in AudioXpress magazine [ 2 ] (see Figure 1). Figure 1. A ...

ADC circuits that resolve signal into 20 or more bits need a low-noise signal source for measuring parameters such as harmonic distortion or effective number of bits. A notch filter removes the fundamental frequency from the oscillators signal for ...

This circuit is a simple sweep generator. The sawtooth is generated by the PNP transistor and the 555 . The transistor together with the 2 diodes at the base form a constant current source which charges the 330 nF capacitor. If 2/3V CC (=6 V) is ...

Figure 1 shows a variation on a sine wave oscillator, it uses just two transistors and a single variable resistor to set the frequency. Figure 1. Just a couple of components are needed for a simple tunable sine wave oscillator. The section around ...

I needed a simple mist maker/humidifier for a project that I was working on. I found lots of ideas on the internet, but they all lacked in one area or another, so I decided to design one. The following lays out my easy-to-build ultrasonic mist ...

A common technique for implementing PWM involves comparing a triangular waveform of fixed amplitude and frequency with a variable dc voltage level. Although this approach results in a PWM signal of precise frequency and with duty cycle variable ...

Usually, noise annoys. Occasionally, it can be a valuable tool. Surprisingly, there is a whole palette of noise colors [ 1 ]. This design idea (DI) shows good ways of generating the commonest and most useful ones, which are white [ 2 ] and pink [ 3 ...

Implementation details Loop area R1/C1/R3 should be minimized for best EMI rejection (Figure 3). Additionally, R1/C1 should be very well shielded from electrical fields, which will be discussed further in the EMI Considerations section. Although ...

The oscillator was intended for other purposes, but unexpectedly its breadboard prototype became in great demand for evaluating the performance of operational amplifiers purchased on well-known Internet sites. The simplest test of the op amp ...