Turn your Digital Voltmeter into an Inductance and capacitance meter. Page 1. Page 2. Products 1 – 20 of 22 Source LCR Meter Accessories at ; the leading distributor of IT, Test Peak Electronic Design LLSm LCR Meter Adapter.
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When the switch S1 is in “C” position, it connects another diode into the circuit, making a voltage doubler rectifier circuit see the Aapter 3. 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.
Any inductance in that path will add to indcutance measured inductance, so keep it short and small. Potentiometer Questions Started by norbss Yesterday at There is a way to check out the duty cycle at the collector of Q1.
The inductance tester converts the inductance value of the coil being tested to a voltage which can be measured by a voltmeter. To participate you need to register. This circuit is only accurate for broadband inductors. I happned to have the 74HC14 in an SO package so I soldered it onto the metalized side of a prototyping board. The procedure is straightforward: Here is the unit measuring a 33 adaptet commercial RF choke.
If not, then match the value of the resistor R7 to make shape of the signal as close to square wave as possible.
LC Connector adapter
You can control lights, fans, AC system, computer, printer, amplifier, robots, garage door, security systems, motor-driven curtains, motorized window blinds, door locks, sprinklers, motorized projection screens and anything else you can think of.
Media New media New comments Search media. Just saying hello Started by MichaelaJoy Yesterday at 6: This site inductnce cookies to help personalise content, tailor your experience and to keep inductace logged in if you register. More precise measurements I do with a resonance bridge. This device is an addon to a digital or analog voltmeter. Connect a battery and a DVM digital volt meterput a emter inductor in the LX position then adjust the potentiometer until you get the anticipated reading on the DVM.
Forums New posts Search forums. C5 in feedback circuits. 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 AT90Sbased 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 jeter making it.
The last inverter in merely to make the pulse positive in polarity so that the inductznce increases as the inductance increases. When you built this, keep the connections, including gorund connections, short because tens of nanoseconds count.
There is a metr possibility that you are using a damaged 74HC14, but check this last since it isn’t very likely. In order to get a pulse with a width that is substantiall longer than the rise and fall time of the schmitt trigger, whcih is a requiremnt for good linearity, while the inductance was in the nH range, I had to use a very low resistance, hence the three ohm resistors and their drivers in parallel.
At first, adjust potentiometers R Inductance and capacitance meter adapter for DVM This device is an addon to a digital or analog voltmeter. The hysteresis in the schmitt trigger allows it to oscillate with the simple feedback circuit.
The schematic diagram for the inductance and capacitance meter is shown in Fig.
It is an irreplaceable tool for troubleshooting and repairing electronic equipment by determining performance and health of electrolytic capacitors.
To my surprise, it actually worked just fine, 1K in series was sufficient to allow a useful calibration and didn’t overload the drive capabilities of the last gate in the package. Headphone amplifier is small enough adapteer fit in Altoids tin box, and thanks to low power consumption may be supplied from a single 9V battery. Started by fastline Yesterday at 8: In the one I built I used a pair of alligator clips soldered to stout wires a couple of cm long.
How the circuit works The schematic diagram for the inductance and capacitance meter is shown in Fig. The Circuit The circuit’s operating principle is that if you make a pulse width proportioal to inductance, metdr keep the pulse frequency and amplitude constant, and then pass the pulse through a low pass filter so that only the average voltage comes out, the resulting DC voltage is proportional to the inductance.
For example, use a 1 microhenry inductor and adjust the potentiometer to get mv on the DVM.
Pay particular attention to the leads and contacts for LX. The pulse frequency is set by a schmitt trigger oscillator composed of a feedback resistance 2k pot and 3. Use an DVM with high input impedance to measure a voltage across the capacitor “C”.
The pulse width is proportional to the inductance and inversely proportional to the resistance. The switch S2 is in position “L”. The output waveforms can be both amplitude and frequency modulated. The circuit relies on a voltmeter with a millivolt range and a high input impedance as a readout device, so it doesn’t have a buffer on the output. This RC network operates as an integrator circuit. Here are some things to check when calibrating: More resources from carbonzit Resource icon.
The transistor Q1 is used to amplify the signal to provide sufficient current through potentiometer R8 and a load circuit.