An excellent selection of easy-to-replicate detector circuits. The first two options are capable of performing two functions at once: a hidden wiring detector 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. Radio signal and hidden wiring detector on a microcircuit
The detector is built on one very common 4001 series chip.
All memory can be quickly mounted using jumpers from single-core wires.
Next, LEDs connected in anti-parallel, a resistor and a power block with an antenna are soldered, in the role of which there is a piece of wire.
The circuit does not require adjustment and, if properly assembled, works immediately when power is applied.
As already mentioned: the detector responds to radio signal radiation and to current-carrying conductors.
2. Detector of hidden wiring and radio signal on transistors
If there is no microcircuit at hand, there will always be transistors. In this example, the most common ones are used – BC547.
The circuit is also very simple. In the circuit, 4 transistors can give excitation, so 3 is used.
The soldering by hinged installation takes no more than 15 minutes.
Check in action.
3. RF signal strength detector
The radio carrier signal detector does not need power and is designed as an attachment to a multimeter.
In this example, assembled on the board.
Connects to the multimeter using terminals from broken probes.
A very necessary thing when setting up local oscillators or other transmitters.