LED Voltmeter
This is a low power voltmeter circuit that can be used with alternative energy systems that run on 12 and 24 volt batteries. The voltmeter is an expanded scale ...
Audio Millivoltmeter
Measures 10mV to 50Volt RMS in eight ranges.
Simply connect to your Avo-meter set to 50µA range. Connect J2 and J3 to an Avo-meter set to 50µA range. Switchi...
Signal Tracer
This simple circuit generates narrow pulses at about 700-800Hz frequency. The pulses, containing harmonics up to the MHz region, can be injected into audio or r...
Mains Voltage Probe
This circuit is not a novelty, but it proved so useful, simple and cheap that it is worth building.
When the positive (Red) probe is connected to a DC positive...
Zener Diode Tester
Using a single 555 Timer IC and a small transformer to generate a high voltage, this circuit will test zener diodes of voltage ratings up to 50VDC. The 555 time...
Distortion Analyzer
The pre-distortion circuit described here is extremely simple (Figure 1) and only requires one trimmer adjustment, though you`ll need an accurate way to measure...
Electrolytic Tester
Firstly, we will describe the "add-on" version for the 5x7 Display as this is the cheapest version and, quite frankly, it only deserves a few dollars as a piece...
Capacitance meter
This project is exactly what you need. It is simple to construct and can be connected to almost any analogue multimeter.
The scales are accurate over each rang...
Continuity Tester II
Our CONTINUITY TESTER gives an audible indication of continuity between the probes so you can keep your eyes on the probe tip. Secondly its response-time is ve...
High Impedance Voltmeter LM358
This circuit is designed to provide an inexpensive way to to create a High Impedance Voltmeter while making use of an inexpensive analog or digital multimeter. ...
True RMS Watt Meter
This circuit will give you a good, Accurate Watt Meter that can measure various power levels.
In the Origional Article the Shunt was a .001 Ohm Copper Shunt gi...
DIGITAL LED AMMETER
Ammeter is a great addition to any Laboratory Power Supply as it will measure the current consumption and help you determine if there are any problems with the ...
1300 Mhz Frequency meter with prescaler
Having found an u664b prescaler chip (Telefunken) from an old tv-tuner , I decided to build a valid frequency counter using pic16f84 , the prescaler I use is a...
Tiny pH-meter
This tiny pH-meter is very tiny: 11cm2 including the PSU circuit! I built it for the College Saint Pierre a few years ago. It is based on a circuit developped a...
Digital Storage Oscilloscope Adapter
A follow up Mk2 version described by EA`s Jim Rowe in the May/June/July 94
issues of EA improved on the original with calibrated time and vertical
scales, and...
Digital Storage Oscilloscope Adapter
A digital storage oscilloscope (DSO) is a very important
piece of test equipment that can do the jobs that a normal CRO
just can`t handle. Suc...
PC-ECAP
Analyze your circuits before you build them!
PC-ECAP has been one of the world`s best linear circuit analysis programs. The software will calculate and plot:...
WinBode
WinBode traces automatically true and asymptotic Bode diagrams of any F(s) function of the complex pulsation....
LCD 7 digit HF counter
The resistor between basis and collector (around 47k) is to be individually set according transistor characteristics. Without PIC in socket at the collector sho...
LCD 7 digit HF counter
The resistor between basis and collector (around 47k) is to be individually set according transistor characteristics. Without PIC in socket at the collector sho...