Circuit LM386 Audio RF Probe Amplifier Signal Tracer 3D board
Circuit LM386 Audio RF Probe Amplifier Signal Tracer 3D board

The Signal Tracer RF and audio probe using Lm386 integrated circuit is geared towards maintaining preamplifier, power amplifiers and even RF devices.
As a probe of audio signal and RF, can make maintenance of equipment such as amplifiers, preamplifier, radios, car audio, transmitters, recorders, televisions and more. The basic operation is to follow the audio signal to a point where it is not available or is undergoing any changes that should not occur.

About circuit audio signal and RF follower for bench maintenance

To learn how to use this tool, I suggest you download this PDF of the Newton C. Braga (Portuguese language) – Using test instruments measure.

Audio  RF Signal Investigator LM386 tool  Circuit LM386 Audio and RF Probe Amplifier   Signal Tracer RF Circuits bench Audio AmplifierThe operation is simple, in two functions:
RF function: the signal will pass through D2, C4 and R1, which form an AM Demodulator circuit, to detect defects in Radio Frequency circuits, the audio will be demodulated and can be heard on the loudspeaker!
AF function: the signal will stop passing through the Germanium diode D2, so you can hear the audio signal amplifier on the loudspeaker! The capacitor C5 prevents any DC component from going to the device being tested. To control the volume we use a potentiometer of 47K. The overall gain of the Lm386 is set to 200, if you wish you can add a potentiometer in parallel with C3 to gain control of the Lm386. The network formed by C7 / R2, guarantees stability to the Amplifier and avoids RF interference.
To power the circuit we use a 9 Volt battery, so it becomes portable, also a 9 Volt DC power supply can be used.

Circuit diagram of the audio and RF Signal investigator

Circuit LM386 Audio and RF Probe Amplifier 700x502 Circuit LM386 Audio and RF Probe Amplifier   Signal Tracer RF Circuits bench Audio Amplifier
Circuit LM386 Audio and RF Probe Amplifier schematic

Suggested printed circuit board for mounting of the circuit

Circuit Audio RF Signal Investigator 700x560 Circuit LM386 Audio and RF Probe Amplifier   Signal Tracer RF Circuits bench Audio Amplifier
Circuit LM386 Audio RF Probe Amplifier PCB
Audio  RF Signal Investigator LM386 700x573 Circuit LM386 Audio and RF Probe Amplifier   Signal Tracer RF Circuits bench Audio Amplifier
Circuit LM386 Audio RF Probe Amplifier PCB layout
Circuit LM386 Audio RF Probe Amplifier PCB silk
Circuit LM386 Audio RF Probe Amplifier PCB silk

List of material for assembly of the circuit With Lm386

PartsValue
Resistor’s 1/4 Watt 5%
R1470K – Yellow, Violet, Yellow, Gold
R210 – Brown, Black, Black, Gold
Capacitors
C1,C6470µF/25V – Electrolytic Capacitor
C2100nF – Ceramic capacitor
C3, C5, C810µF / 25V – Electrolytic Capacitor
C4270pF – Ceramic capacitor
C747nF – Polyester or Ceramic Capacitor
Semiconductors
D11N4004 or equivalent – silicon diode rectifier
D21n34 or equivalent – Germanium Diode
IC1LM386N-1 – Integrated circuit audio amplifier – Dil8
Connectors
INConnector for RF  or Audio signal input
OUTConnector for speaker
Miscellaneous
DC_9VJack to power, connect the external power supply
P147K – potentiometer
BAT9V Volt battery
Solder, wire, PCB, box, test lead, etc..

Download Files for mounting the Signal Investigator – PDF, Printed circuit board, Circuit diagram, Layout and Silk Screen components, LM386 Datasheet.
Download PDF     Mirror

Buy diy kit LM386 amplifier in Aliexpress

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