An excellent selection of easy-to-follow detector circuits. The first two options are capable of performing two functions at once: a detector of hidden wiring and a radio signal. The latter is able to determine the power of the carrier radio signal. This small attachment to the multimeter will help in setting up or searching for radio transmitters.
1. Detector of radio signals and hidden wiring on a microcircuit
The detector is built on one very common 4001 series microcircuit.
The memory can all be quickly mounted using jumpers made of single-core wires.
Next they are soldered LEDs connected back-to-back, a resistor and a power supply with an antenna, which is a piece of wire.
The circuit does not require adjustment and, if assembled correctly, works immediately when power is applied.
As already mentioned: the detector reacts to the emission of a radio signal and to current-carrying conductors.
2. Detector of hidden wiring and radio signal using transistors
If you don’t have a microcircuit at hand, there are always transistors. In this example, the most common ones are used - BC547.
The circuit is also very simple. In the circuit, 4 transistors can provide excitation, so 3 is used.
Overhead soldering takes no more than 15 minutes.
Testing in action.
3. Radio signal power detector
The radio carrier signal detector does not require power and is designed as an attachment to a multimeter.
In this example it is assembled on a board.
Connects to multimeter using terminals from broken probes.
A very necessary thing when setting up local oscillators or other transmitters.
