Twisted Pair Video Cable Driver and Receiver Circuit

Twisted-pair wiring is a wiring technique that usually used for in-building data communication. Compared to conventional coaxial-cable, this technique offers substantial cost saving, for video transmission on the same medium. A differential driver is used to launching a baseband camera signal to twisted pair. Twisted pair exhibits a roll-off characteristic is that need equalization to correct for. The differential driver and the corrector circuit. This is the figure of the circuit;


This differential driver uses two LT6652, one is used to create a gain of +1 and another is used to make a gain of–1. Besides that, LT6652 is used to reject any ground noise and prevent ground loops via the coax shield. The signal is terminated and re-amplified to re-create an unbalanced output for connection to recorders, display monitors, etc when the signal at the receiving end of the cable. The amplifier must provide the 2x gain required output drive and make up for the losses in the cable run.

[Circuit source: Linear Technology Application Notes]

Linearized Platinum RTD Signal Conditioner Circuit

The best choice for stability and high accuracy in temperature measurements is Platinum resistance temperature detectors (RTD). However, the signal conditioning is complicated by the RTD which exhibit a non-linear temperature versus resistance characteristic. The non-linearity amount of 0 C to 100 C is up to 0.4 C. This is the figure of the circuit for Linearized Platinum RTD Signal Conditioner;

This circuit use A1 as a negative gain inverter to drive a constant current across the platinum sensor. The current reference is provided by the 1oK resistor and LT1009. The self heating induced errors reduced and the voltage through the RTD is low because A1 operates at negative gain. The platinum sensor’s temperature varies A1’s output potential and fed to A2.

The offsetting and scaled gain are provided by A2. Therefore, the A2’s output will swing 0.00V to 10.000V for 0.00 C to 100.00 C temperature swing at the RTD. The noise pick-up is limited by the 1uF capacitor. Returning a small portion of the circuit’s output to A1 will correct the 0.4 C non linearity error due to the RTD’s imperfect response. This circuit is calibrated by substituting the sensor with a precision decade box. The deviation of the each sensor is different depends on the manufacture that produced it. The purity of the material fix the gain slope of the platinum.

[Schematic circuit source: Linear Technology Application Note]

Adjustable High Power LED Driver Circuit

This is a circuit that can drive three to four high power LEDs is shown on figure below. The ADP 1610 is an adjustable boost regulator. The voltage headroom and current for the LEDs is provided by this device. An average gain of 12 feedback network that servos the Rset voltage and the ADP1610 FB pin 1.2 V band gap reference voltage is formed by the AD5228 and the op amp. The voltage across Rset is regulated around 0.1 V and adjustable by the digital potentiometer as the loop is set. This is the figure of the circuit;

I led = Vrset/Rset

To conserve power but large enough to limit maximum LED current, Rset should be small enough. To limit the LED current within an achievable range, R3 should also be used in parallel with AD 5228. By lowering the R2 to R1 ratio as well as changing R3 accordingly, a current adjustment range can be expanded.

[Circuit source: Analog Devices Application Note]

Dual-Output Gate-Driver Approach Using the LM25037 Controller

This is a design circuit for basic schematic of the LM25037 dual gate driver switching the gates of two FETs independently. This is the figure of the circuit;


Switching two independent FETs from a dual gate drive controller typically allows the designer to select low RDSON FETs with a higher gate charge. Higher gate-charge FETs tend to be less expensive than their lower gate-charge counterparts. The two FETs selected to be switched independently are the SiR468DP. As previously mentioned, driving two FETs in parallel produces a 50% reduction in RDSON. Switching FETs independently, however, no longer yields the 50% reduction in RDSON but transitional losses are reduced.

[Circuit source: National Semiconductor Application Notes]

Single Gate-Drive Parallel-FET Approach Using the LM5020 Controller

Considering the previously-identified specification, the designer may opt to use National’s LM5020 PWM controller. This is a design for application from LM5020. This is a single gate driver parallel FET circuit. This is the figure of the circuit;


Placing two FETs in parallel will increase switching losses as the gate charge will double and therefore switching transition times will double. With high RMS switch currents and the doubling of gate charge, it is essential to select FETs that have a low RDSON and a low gate charge. These types of FETs tend to be more costly than FETs that have similar RDSON with a higher gate charge. To address this transitional loss issue, the FET selected for this example is the SiR472DP FET from Vishay.

[Schematic circuit source: National Semiconductor Notes]

Stereo Line Driver Circuit

This is the schematic diagram of a low cost stereo line driver. The circuit is based only two transistors and few passive components. The circuit has simple design. This is the figure of the circuit.


The description work of the circuit is each BC 109C transistor is wired as an emitter follower for driving each channel. The voltage gain of the emitter follower is unity, but it has a high current gain and low output impedance, ideal for driving long cables. The output impedance is around 16 Ohms at 1KHz.Since voltage gain is unity power amplifiers must be used at the listening end in order to drive loud speakers. The circuit can be powered from a 12V battery or 12V DC power supply. A power amplifier is needed at the listening end because the emitter follower has only unity voltage gain. The inputs and outputs must be connected with respect to ground as shown in circuit.

LED Driver Circuit with Transistor

This is a design of LED driver circuit. This circuit is work with based on 2two transistor. This circuit is very simple project. This is the figure of the design circuit.


The operation of the circuit is begin from the output current is almost constant over an input-voltage range of 1.2 to 1.5V and is insensitive to variations of transistor gain. Transistors Q1 and Q2 form an astable flip-flop.R1 and C define the on-time of Q2. During that time, Q1 is off, and the voltage at the base of Q1 and the current in inductor L ramp up. When the voltage at the base of Q1 reaches approximately 0.6V, Q1 turns on, and Q2 turns off. This switching causes “fly back” action in inductor L. The voltage across the inductor reverses, and the energy stored in the inductor transfers to the LED in the form of a down-ramping pulse of current. During fly back time, voltage across the LED is approximately constant. The voltage for yellow and white LEDs is approximately 1.9 and 3.5V, respectively. When the current through the LED falls to zero, the voltage at the collector of Q2 falls sharply, and this circuit condition triggers the next cycle

DoZ Preamp as a Driver Using Transistor

This is the circuit for pre amp that is used as driver. This is a simplest form of the driver. The circuit is controlled by transistor. This is the figure of the circuit.


The modified version of the preamp that is show by the figure is the output of which would be connected directly to R1 in the circuit. The quiescent output voltage is now set by VR1 in the preamp, and the voltage at the source of T1 should be set to 19.8V as shown in Figure 1 by means of VR1 - the voltage at the gate (preamp output) should be 4V higher, i.e. 23.8V. The DoZ preamp board is stereo, and can drive a pair of the power followers with ease. Q2 and Q3 should be fitted with small "flag" heat sinks to allow them to dissipate the increased power caused by the higher operating voltage.

120 VAC Dimmer Lamp Driver Circuit

It is a simple design full wave phase control. This circuit is supplied by AC line. In this circuit is there the four diodes provide a full wave rectified voltage to the anode of a SCR. The figure in below is the circuit.


This is a principle work of the circuit. Two small signal transistors are connected in a switch configuration so that when the voltage on the 2.2uF capacitor reaches about 8 volts, the transistors will switch on and discharge the capacitor through the SCR gate causing it to begin conducting. As the resistance is reduced, the time is reduced and the SCR will conduct earlier during each half cycle which applies a greater average voltage across the load. With the resistance set to minimum the SCR will trigger when the voltage rises to about 40 volts or 15 degrees into the cycle. To compensate for component tolerances, the 15K resistor can be adjusted slightly so that the output voltage is near zero when the 50K pot is set to maximum.

8 Watt Flouroscent Lamp Driver

This is a design circuit of a simple flouroscent lamp driver circuit based on two transistors. The circuit uses capacitive ballasting for driving the tube. An 8 Watt standard flouroscent tube can be efficiently driven using the circuit. This is the figure of the circuit.


The two transistors (2SC1983) with associated components form an oscillator around 1KHz. The oscillator is wired so that saturation conditions of the transistors are prohibited. This adds on to the efficiency of the circuit. The circuit produces a clean sine wave with very less noise. The winding details (no of turns) are given in the circuit. Use 0, 8 mm diameter enameled copper wire for primary and 0, 4 mm diameter enameled copper wire for secondary. The core can be a ferrite core. The primary should be wound first and secondary on top of it. The circuit is use a 12 V battery or 12 V DC power supply as the DC voltage source.