Hello, friends!
In continuation of the articles on amplifiers, I think the circuit of a logarithmic signal level indicator will also come in handy. This device is based on the LM3915 microcircuit in the amount of two pieces (each microcircuit works on its own channel), you can see detailed information about the microcircuit, the recommended supply voltage is 12V. The LM358 chip acts as a pre-amplifier. Detailed information about the chip.
In place of LM3915, you can use the following similar microcircuits: LM3914 and LM3916. It is worth considering that the jackal chip 3914 is linear, the LEDs light up in steps of 3 dB, and the steps 3915 and 3916 are logarithmic.
In place of LM358, you can use the following similar microcircuits: NE532, OP04, OP221, OP290, OP295, OPA2237, TA75358P, UPC358C.
Advantages of this device
- Easy to manufacture
- Reliability
Flaws
- High cost of the microcircuit. This drawback is eliminated by purchasing radio components in China.
Stereo signal level indicator circuit
Signal level indicator circuit board
List of radio components
Microcircuits. To install microcircuits on the board, I recommend purchasing an additional DIP18 socket and installing the microcircuits into the socket last. In order to reduce the likelihood of failure of the microcircuit due to static electricity when it is installed on the board.
- LM358 — 1 piece
- LM3915 - 2 pcs.
Resistors
- trimming resistor RV1 and RV2 - 100 kOhm - 2 pcs.
- R1, R2 - 22kOhm -2pcs
- R5, R6 - 220 kOhm - 2 pcs
- R3, R4 - 1kOhm - 2 pcs
- R7, R8 - 47kOhm -2 pcs
- R9, R11 - 1.3kOhm -2pcs
- R10, R12 -3.6 kOhm — 2 pcs.
Capacitors
- 1.0 mF - 4 pcs
- electrolytic capacitor 100mF x 32V - 1 piece
- 1N4148 - 4 pcs.
- LEDs - 10 pcs. Selected according to taste with a supply voltage of 3V. We recommend choosing the last two LEDs in a different color.
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