This video reviews the two most common reasons why the output amplitude setting on a function or signal generator doesn’t match what is read on an oscilloscope. This can be due to an incorrect attenuation setting on the scope, but is most commonly due to the fact that the generator is not presented with the load impedance that it is expecting. To correct this most common case, you can either use the correct load impedance, or tell the generator what load you are presenting it with.
Why your Function Generator’s output voltage reading can be wrong - [Link]
This video discusses how to measure the ESR (equivalent series resistance) of a capacitor using an oscilloscope and function generator. All of the capacitors tested in this video were 220uF electrolytic caps. In reality, the resistance in the plates of a dried out electrolytic capacitor can’t be modeled as a simple series resistor, but for the purposes of identifying good from bad, this simplification works fine.
Measure Capacitor ESR with an Oscilloscope and Function Generator - [Link]
Harrymatic @ instructables.com writes:
I was in need of a function generator to produce audio signals for testing effects / amplifiers; as well as TTL clock signals for digital circuits. As function generators generally cost about £200 new, I decided that I would instead build one myself.
This project uses the XR-2206 integrated circuit to generate the waveform. It can produce sine and triangle waves of selectable amplitude and frequency and also a TTL sync signal fixed at 5V. The frequency range is about 20Hz to 300KHz – so this function generator will easily cover the full human hearing range of frequencies.
Analogue Function Generator - [Link]
amandaghassaei @ instructables.com writes:
Waveform generators (also called function generators) are useful for testing and debugging circuits. They can be used to test the frequency response of electronic components like op amps and sensors or to characterize and troubleshoot audio effects boxes and pedals. This waveform generator shield is powered by an Arduino. It outputs four waveforms: sine, triangle, pulse, and saw, each waveform ranges in frequency from 1Hz-50 kHz. The frequency, pulse width, and overall amplitude (gain) of the waveforms is controlled by three potentiometers.
Arduino Waveform Generator Shield - [Link]
manekinen @ mdiy.pl builds a 400KHz function generator based on ICL8038. He writes:
Function generator with adjustable frequency from 0 Hz to over 400 kHz, adjustable amplitude, DC offset, duty, and of course the function selection – square, triangle, and sine. Generator based on good old ICL8038 integrated chip generator that gives pretty good shaped signals as for amateur purposes.
400kHz function generator with ICL8038 - [Link]
The AD9837 is a low power, programmable waveform generator IC capable of producing sine, triangular, and square wave outputs. Below is a circuit design to build your own function generator. The circuit can be connected to a microcontroller through a 3 wire serial interface to set the registers in the waveform generator IC. Package it in a nice enclosure and add some BNC connectors and you have your own Function Generator.
A modular system of laboratory devices Hameg 8000 series is an ideal system for testing workplaces and school laboratories. At the same time it enables a very effective usage of space.
To have all we need on a table and to maintain enough space for a work – it is a stable challenge at a work with electronics. We may say, that for example a generator won´t be on my table today. But as it uses to be, after a while we´ll find we need just that instrument, which is missing on a table. Sometimes a solution is to stock them at each other, but we usually face the problem with a different size of instruments, or eventually also an instability of such a “set”. All this is solved by a Hameg 8000 series modular system.
The system consists of a HM8001-2, main unit, serving as a power supply and at the same time it is a holder – frame for any 2 instruments from the 8000 series (instruments don´t have their own power supply – for their operation they need to be inserted into the HM8001-2 basic module). Up to 5 such mainframes can be stocked at each other, what means up to 10 instruments. That brings a big saving of space and especially a comprendious and safe work. At the same time, it enables a big variability – for example usually a one mainframe + 2 instruments (according to an actual need of a given lesson) are usually sufficient for students in school.
- HM8012 – 4¾-Digit Programmable Multimeter (max value 49999) with 0.05% basic accuracy, max. resolution: 10μV, 0.01dBm, 10nA, 10mΩ, 0.1°C, offset function and a relative value measurement, including an RS232 interface and software
- HM8018 – 25kHz LCR-Meter, measures L, C, R, Θ, Q/D, |Z|, 0.2% basic accuracy, 5 measuring frequencies (100Hz, 120Hz, 1kHz, 10kHz, 25kHz), max resolution: 0.001Ω, 0.001pF, 0.01μH, 2- and 4-wire measurement, parallel and serial mode
- HM8021-4 – 1.6 GHz Universal Counter, measurement range 0Hz…1.6GHz, 10MHz time base with 1ppm stability, 2 inputs – 1MΩ/ 50Ω
- HM8030-6 – 10 MHz Function Generator, frequency range 50mHz…10MHz, output voltage up to 10Vpp (do 50Ω), waveforms: sine wave, triangle, square wave, pulse, DC, distortion <0.5% up to 1MHz, rise and fall time 15ns typically, internal and external sweep, FM (with option HO801), surge- and short-circuit-proof (ideal for testing and educational conditions)
- HM8040-3 – Tripple Power Supply Unit 2x 0–20V/0.5A – 1x 5V/1A, 3-digit switchable displays (resolution 0.1V/1mA) , Pushbutton for activating/deactivating all outputs, adjustable current limiting and electronic fuse, low residual ripple and low noise
- HM800 – Blank Module intended for customized instrument construction, inner guide for PCB mounting in 4 various levels, plastic front panel for easy mechanical processing, power is supplied by the HM8001-2 mainframe
As can be seen from this description, those are the quality instruments with very decent specification and with an excellent price/ performance ratio. Excellent properties are mainly proven in praxis, in a form of several 100 000 units sold all over the world. Detailed information will provide you datasheets at particular modules, series 8000 overview and the overview of options. In case of interest in any Hameg or Rohde&Schwarz instrument, please contact us at firstname.lastname@example.org
With the Hameg 8000 series devices you always have on a table all you need - [Link]
We know, that there are a lot of designs out there, but this one offers :
• Amplitude and Offset tunable for all (Sine, Triangle and Rectangle) Waveforms
• Output Voltage can be as high as 70 Vpp (useful for scanning piezos)
• Built-in Clipping Detection
• Built-in Frequency Counter (with ATmega8)
• AM Modulation Input (controls Sine and Triangle only)
• FM Modulation Input (controls all Waveforms)
• Sync Output (TTL)
• min < 1 Hz, max > 100 kHz in 5 (widely) overlapping ranges (Standard Version)
• min < 1 Hz, max > 10 kHz in 4 (widely) overlapping ranges (High Voltage Version)
XR2206 Function Generator - [Link]
This is a 1Hz – 2MHz XR2206 Function Generator kit that produces high quality sine, square and triangle waveforms of high-stability and accuracy. The output waveforms can be both amplitude and frequency modulated. Coarse frequency adjustment is accomplished using 4-DIP switch for the following four frequency ranges; (1) 1Hz-100Hz, (2) 100Hz-20KHz, (3) 20KHz-1MHz, (4) 150KHz-2MHz. Frequency output can be fine tuned using P1 and P2 potentiometers.
1Hz to 2MHz Function Generator with XR-2206 IC – [Link]