VU (Voltage Unit) meters are often included in analog audio equipments to display a signal level in Visual Units. We are building a mono input VU meter in this project. You can build one pair to use them in stereo mode.
Structure: Input sensitivity is about 1 Volt rms, up to +6dB. You can adjust the input amplitude by using the multiturn 50k linear potentiometer (POT1). Circuit needs symmetric ±12V power supply because of the LM324 opamp. We used metal film resistors (1% Tolerance) so accuracy is sufficiently high. Visual duration can be adjusted by using linear 10k potentiometer (POT2). LEDs should be 5mm x 5mm in size for best fit. But we used standard LEDs and this caused a little shift as you can see from the image. Dot/Bar switch determines the operation mode of LM3915.
PCB is 1:1 scaled. You can print and transfer without making any change.
Click here to download schematic, layout and PCB files.
Here you can see the performance of the VU Meter in bar mode,
This circuit provides a fully protected, 100% automotive proof, low voltage and low consumption proposal for driving additional (or existing) 2x55W bulbs (high beams). Superior ruggedness and reliability is offered by means of a pure Solid State Switches solution.
The advantages of using semiconductors are manifold:
• They are substantially more reliable and durable than mechanical relays.
• They are smaller and lighter.
• They incorporate self-diagnostic capabilities.
• They offer self-protection and external protection capabilities.
• You can find practically any functionality you need.
Electromechanical relays are constantly being replaced by high-side drivers, which are also known as intelligent power switches or IPS. These devices are commonly made in a monolithic technology in which a vertical Power MOSFET (power output) is integrated with a low-voltage control circuitry based on NMOS components. The availability of the low-voltage control circuitry allows the implementation of standard protections require...
This is a two part infraredremote controller circuit that consists of a
transmitter and a receiver circuit pair. When you push the button on
the 9V supplied transmitter circuit, a signal at 38kHz frequency is
applied on the Infrared (IR) LED. As a result of the current passing
through the IR LED, it illuminates the surround with infrared light.
By using the 1k potentiometer, oscillator frequency should be adjusted
to 38kHz to operate the circuit properly.
The illuminated infrared light is detected by the IR receiver module.
Generally IR modules has three pins and in our project we used the
product of Telefunken, TK19 module. Instead of TK19, as an option you can use the SFH506 which is a product of Siemens or any other module for this purpose.
When the IR light touches the receiver, the third pin of the module sees
logic-0 (low). Other case it is in the logic-1(high) position. So
controlling the third pin gives us the information whether the button
on the transmitter is pushed or not.
The J-K type flip flop in the receiver circuit controls the relay. When
the button is pushed, relay gets in the position closed which was in
open position before. So the device gets connected to the mains and
starts operating. After second push, relay gets in position open and
cuts the device energy...
