SSL3250A Photo Flash LED Driver Circuit

This device ensure a lot of implementation possibilities because it has wide input voltage range and the large maximum output current at a wide output voltage range. It has long battery life and low power strain because of it’s high efficiency and soft-start. This device has many features which is can be used to protect the battery and LED from overloading, and result in trouble-free operation of the whole mobile application such as overvoltage, over temperature and feedback shorted protection, under voltage lockout and time-out function. This is the figure of the circuit;


This device (SSL3250A) has two general control modes: Direct control (the lower circuit schematic diagram) and I2C Control (the upper circuit schematic diagram). The IC is designed to be directly controlled by the application in direct control mode. To change the timing and current settings of the SSL3250A, we can use I2C control. We can also use I2C control to switch the driver to Flash mode, Torch mode or Indicator mode. EN1 and EN2 are used in Direct control mode. SCL, SDA, and STRB are used in I2C control mode. In a typical application, we only allowed to use one control mode.

FM Radio Receiver Circuit for Battery Supply

This is a schematic for radio receiver circuit. This circuit is based on the TDA7088T that can be used in mono portable and pocket radios. This is a bipolar integrated circuit. This is the figure of the circuit;


When a minimum of peripheral components (of small dimensions and low cost) is important, we can use TDA7088T. Frequency-locked -loop (FLL) system with an Intermediate Frequency (IF) of about 70 KHz is built on this circuit. By active RC-filters, selectivity is achieved. De-tuning related to the IF and the mute circuit is suppress too week input signals. [Schematic circuit source: NXP Semiconductor Application Notes]

Avoiding Electrolysis For Water Level Detector Probes Using Alternating Current Detection

Electrolysis process has been the primary cause of your water level detector probes, and you can avoid this by sensing the current by this probe using alternating current. In alternating current, the electrolysis process will be reversed for every alternating cycles, making the probe will last longer to survive from corrosion. This is the figure of the electronic circuit for this alternating current sensing for water level detector.


The whole circuit consists of oscillator and detector. The oscillator is build around U1A. The capacitor C2 is inserted between the oscillator output and the probe to block DC signal, same as the C3 capacitor function. When the probe is submersed under water, an alternating current generated by the oscillator will flow through C2, probes, and C3. The alternating current from C3 is then rectified by D2 and filtered by C4 to get back the DC voltage. The diode D1 is provided to give the back flow path for the alternating current. Without D1, the alternating current won’t flow since the D2 diode only permit the current to flow for one direction. The DC level is detected on C4 and then its trigger the U1B gate to turn on the relay. You can control a water pump using the relay output to turn on the pump if the water level is below the probes, and turn off when they’re submersed.

Audio Graphic Equalizer Circuit

This is a project circuit for audio equalizer. This circuit is control by single chip op amps. This is the figure of the circuit;


A gyrator is a circuit using active devices and transistors to simulate an inductor. In this case the gyrator is the transistor acting with R1, R3 and C2. It could just as easily be a unity gain op-amp (which gives superior performance). The circuit includes three formulae: one which gives f, the centre frequency of the band. The second shows how the Q is related to the capacitor ratio. The third shows the impedance presented by the circuit. Note that this includes 3 terms, the first purely resistive, the second is the capacitive contribution from C1 and the third is an inductive term from the gyrator.

AM/FM/SW Active Antenna Circuit

This is a circuit diagram for active antenna that can be used for AM, FM, and shortwave (SW). On the shortwave band this active antenna is comparable to a 20 to 30 foot wire antenna. This circuit is designed to be used on receivers that use un-tuned wire antennas, such as inexpensive units and car radios. This is the figure of the circuit.


L1 can be selected for the application. A 470uH coil works on lower frequencies ( AM ). For shortwave, try a 20uH coil. The unit can be powered by a 9 volt battery. If a power supply is used, bypass the power supply with a .04uF capacitor to prevent noise pickup. The antenna used on this circuit is a standard 18" telescoping type. Output is taken from jack J1 and run to the input on the receiver.

3 Band Equalizer Circuit

This is a circuit for a tone control using 3 band equalizers. This circuit is based on single chip op amps LF351. This circuit having three ranges, bass, middle and treble controls. This is the figure of the circuit;


With a single chip op amps LF351, it is easy to make equalizer offers three ranges, low frequency, mid frequency, and high. With component values shown there is approximately +/-20dB of boost or cut at frequencies of 50Hz, 1kHz and 10kHz. Supply voltage may be anything from 6 to 30 Volts. Maximum boost 20dB is only realized with maximum supply voltage of 18 Volt.