Rongge

Minimalist Dip Meter Circuit Diagram. In days gone by a radio amateur always had a dip meter close to hand in his ‘shack’. Now that people can afford oscilloscopes, the poor old dip meter has lost its importance and is  frequently no longer to be seen. Actually this is a shame because many tasks are much easier to carry out with a dip meter. Anyone who’s interested (perhaps the second time around) can easily build one rapidly with this very simple but adequate circuit. The interesting question is namely what do you actually need from a dip meter?  Minimalist Dip Meter Circuit Diagram A visual display of the dip? Nope, the ‘scope can handle that task. A large frequency scale? Not necessary, as you can connect a frequency counter for this. A selection of coils? We don’t need these because we can use a jumper to change range (no coils to lose any more!). The sensor coil L1 has ten turns and is wound  using an AA-size battery as a former. This coil will allow us to over the ...

The post explains a very handy little decibel meter circuit which may be built by any new hobbyist at home. Description Decibel (dB) is a unit of sound pressure. In this particular circuit three LEDs or lamps are employed to indicate the pressure of a available audio input. When the three lights are ON, the audio level would be 4x. When two lights are ON it would be 2x and when one light ON it would be x. the circuit is built around a quad OP-AMP LM324. One section of the IC is being used as an amplifier whereas the other three OP-AMPs have been used as voltage comparators. Here in this case the audio sensor is a standard 8ohm speaker. One side of the speaker is grounded and the other pin of the speaker is connected to the negative pin of a 10μF electrolytic capacitor. The positive pin of the electrolytic capacitor is connected to the base of a switching transistor of high gain. In this case 2N2222 or 2N3904 is recommended. The first OP-AMP which is used as an amplifier as a trim p...

This is a simple project of ESR and Low Resistance Test Meter Circuit Diagram. As electrolytic capacitors age, their internal resistance, also known as "equivalent series resistance" (ESR), gradually increases. This can eventually lead to equipment failure. Using this design, you can measure the ESR of suspect capacitors as well as other small resistances. Basically, the circuit generates a low-voltage 100kHz test signal, which is applied to the capacitor via a pair of probes. An op amp then amplifies the voltage dropped across the capacitor’s series resistance and this can be displayed on a standard multimeter. In more detail, inverter IC1d is configured as a 200kHz oscillator. Its output drives a 4027 J-K flipflop, which divides the oscillator signal in half to ensure an equal mark/space ratio. Two elements of a 4066 quad bilateral switch (IC3c & IC3d) are alternately switched on by the complementary outputs of the J-K flipflop. One switch input (pin 11) is connected to...

This is an audio meter, a kind of decibel simpler, used to measure the sound directly in the circuit or a sound output device. It is very simple, using only two transistors BC107, potentiometer VR2 adjusts the input level and the level of VR1 VU. This meter audio should only be used for bench testing and should not be used for calibration. Simple Audio Meter Circuit Diagram Simple Audio Meter Circuit Diagram