Low Speed AVR Oscilloscope
A few months ago as I was surfing on the net, I saw an oscilloscope based on PIC18F2550 microcontroller and a KS0108 controller based graphical LCD. That was Steven Cholewiak's web site. I had never seen before so amazing microcontroller - only oscilloscope. That was realy impressive circuit, so I decided to design something like that but in C language instead of assembly that I was using all those years. The best solution for me was the WinAVR as it bases on open source AVR - GNU compiler and it works perfect with AVR studio 4. The graphics library that I used, is made by me specific for this project. It's not for general use. If you want to include it to your codes, you have to convert it as you need to. The maximum signal speed who can show up this oscilloscope is 5 kHz in square signal. For other signals (sine or triangle) the frequency is lower ( almost 1 kHz) for having clear view of the signal.
This is simple MAX038 generator. It produces sine, triangle and square waves from 1Hz up to 22MHz. The Amplitude, offset and duty cycle are adjustable to offer wide range of generated signals.
Frequency adjustment is made as a rotary switch S8 with a capacitor bank and variable resistor P7. Amplitude, offset and duty-cycle are performed via variable resistors. Switch S5 selects generated waveform.
Oscilloscope ESR Tester
When teamed up with an oscilloscope, this simple circuit provides a means of measuring capacitor ESR.
A 555 timer (IC1) configured as a 2.3kHz free-running oscillator acts as the timebase. It provides narrow (7.7µs) pulses to the capacitor under test via a NAND Schmitt trigger (IC2) and transistor Q1.
A 100Ω resistor in series with Q1 limits current flow to about 50mA. Therefore, an ESR of 1Ω will produce pulses across the test capacitor of 50mV, which means that an oscilloscope with a vertical sensitivity of 5mV can measure ESR down to 0.1Ω or less.
Oscilloscope Probes for Accurate Signal Measurements
On the following article learn about Oscilloscope probes, their basic characteristics and proper calibration. Measuring signals with oscilloscopes may be challenging task especially high frequency ones. Without proper oscilloscope probes correct measurement of high speed time domain signals wouldn’t be possible. For high speed measurement you should consider signal parameters like amplitude, source impedance, rise time and bandwidth.
PIC Frequency Counter
Programmable frequency meter with PIC16F84 and UPB1505 prescaler
PIC Volt Ampere Meter
PIC Voltmeter Amperemeter can measure voltage 0-70V or 0-500V with 100mV resolution and current consumption 0-10A or more with 10mA resolution. The meter is a perfect addition to any power supply, battery chargers and other electronic projects where voltage and current must be monitored. The meter uses PIC16F876A microcontroller with built-in ADC (Analog to Digital Converter) and 16x2 green backlighted LCD display. With slight modification it is possible to measure higher voltage and current.
PIC Voltmeter Amperemeter
This PIC Volt Ampere Meter was designed to measure output voltage of 0-70V or 0-500V with 100mV resolution and 0-10A or more current with 10mA resolution. It is a perfect addition to any DIY laboratory power supply, battery chargers and other electronic projects where voltage and current consumption must be monitored. Thanks to added calibration via SETUP, UP & DOWN buttons it is now possible to calibrate the meter to measure voltage that is higher than 70V and current that is greater than 10A.
PIC16F84A 3.5GHz LCD Frequency Counter
This Auto Ranging PIC16F84A Frequency counter counts up to 35-40Mhz and has two separate input BNC connectors. A pre-scale chip from Nec/CEL may be added with Divide by 256 counters to achieve 3.5GHZ frequency measurements.
PIC16F877 APRS Weather Station
Weather Station is PIC16F877A based and has a 4x20 LCD, a data logger output and accepts 1Wire wind instrument. It has a built-in APRS TNC. Connect it to your portable rig thru a DIN5 connector and you have a true portable weather station.
RF Inductance Meter
This RF inductance meter measures RF chokes in the 500 nH to 50 uH range. I needed a way to measure hand-wound RF inductors in my second lab, and since I would only be doing this occasionally, I didn't need anything fancy, and since once a friend finishes his AT90S1200-based design, I plan to make one myself, I figured I'd use this for less than a year, so I didn't want to invest a lot of time in making it . I had run across the forerunner of this circuit, one that is more sophisticated in that it has a zero adjustment and range switch, but it was limited to higher inductances. I adapted it to the components I had on hand and changed it so that it would work in the 500 nanohenry to 50 microhenry range.The original circuit was reportedly published a few years ago by the Amrican Radio Relay League, so it is with appreciation of the ARRL that I make this circuit available