Simple Programmable Current Source/Regulator Circuit

This is a simple circuit of programmable current source/regulator. This circuit is used to generate current. This is the figure of the circuit;

This circuit uses L 200 as main component. The error amplifier of this circuit is disabled by shorting pin 4 to ground. The value R is used to fix the output Io :

Io=(V5-2)/R
The output voltage can reach a maximum value Vi
– Vdrop=Vi 2 V (Vdrop depends on Io ).

Simple Precision Power Regulator Circuit

Making a precision voltage source is easy, but not so easy if the voltage should be consistent over wide range of ambient temperature. Such requirement might be needed in high precision measurement system, for providing reference voltage in analog to digital conversion for example. This is a design circuit for precision power regulator. This is the figure of the circuit;

This circuit is based on LM 336. LM336 voltage references are easier to use than zener diodes. Their low impedance and wide current range facilitate biasing in any circuits. Besides, the breakdown voltage or the temperature coefficient can be adjusted so as to optimize the performance of the circuit. [Circuit diagram source: STMicroelectronics Application Note]

Simple Shunt Voltage Stabilizer Circuits

This is a circuit for a simple voltage stabilizer circuit that employs a zener diode and a single resistor. In this circuit, the zener diode, which is the stabilizing component, is in parallel (or in shunt) with the load, which is why it is also called a shunt stabilizing circuit. This is the figure of the circuit;

The value of R must be chosen so that a 'holding current' of 2 mA will flow into the zener diode even at the lowest input voltage and maximum load current. The zener diode maintains the output voltage level by 'conducting' the excess current to ground whenever the voltage across it becomes excessive.

Simple Series Voltage Stabilizer Circuits

This is a circuit for simple voltage stabilizer circuit that employs a resistor, a zener diode, and an NPN transistor. In this circuit, the zener diode is used to stabilize the base voltage of the NPN transistor, which carries the load current. This is the figure of the circuit;

The load transistor is in series with the load, which is why this circuit is also known as a series stabilizer. Unlike the amplified zener shunt stabilizer, the dissipation of the transistor increases only when the actual load current increases, making its operation more efficient.

Simple DC Voltage Ripple Remover Circuit

This is a circuit for a simple circuit for removing an AC ripple from a DC voltage. The main component of the circuit is an operational amplifier configured as a simple amplifier in common-mode operation. This means that both the inverting and non-inverting inputs of the op-amp get the same input voltage, i.e., a DC voltage Vin with an AC ripple Vripple. The only difference is that the inverting input has an input capacitor that blocks the DC voltage. This is the figure of the circuit;

Since the op-amp amplifies just the difference between the voltages at its two inputs, it cancels out the AC ripple (which appears at both inputs). On the other hand, the op-amp amplifies the DC voltage Vin since this is only present at the non-inverting input. However, the op-amp is configured to have a DC voltage gain equal to 1, so the output of this circuit is just equal to Vin. Since the AC ripple can only be cancelled cleanly if both op-amp inputs have equal gains, the 10K potentiometer is used to compensate for any inherent differences between the inputs' gains.

Simple 3A Switching Regulator Circuit

This is a design circuit for a simple and low cost switching regulator using the IC LM317 that can deliver up to 3A of current. The input voltage range of this circuit is between 8 to 35V DC and the output voltage can be adjusted between 1.8 to 32V DC. The output voltage can be adjusted by using the POT R4. This is the figure of the circuit;

When compared to linear voltage regulators the switching voltage regulators are much power efficient. In the case of linear voltage regulators the difference between the input and output voltage is just wasted and for switching regulators there is almost no such wastage and that’s why the switching regulators have great power efficiency ranging up to 85% . In simple words, the switching regulator operates by taking small bits of energy from the input voltage source and then transferring it to the output with the help of a solid state switch and a control circuitry. Since the switching element is either fully open or closed at any moment, no energy is wasted across it. The control circuit controls the duty cycle of the solid state switch which in turn determines rate at which energy is transferred to the output.

Simple 3 Band Tone Control Circuit

This is a design circuit for the simple design of a 3 Band Tone Control Circuit Diagram. This is the figure of the circuit;

R1 is left up to the user depending on gain needs. This circuit design was originally intended for home audio use, but should be able to hacked into an effect circuit with very minor modification.

Simple Voltage Doubler Circuit

This is a design circuit that is output a voltage Vout that is approximately twice the level of the Vcc voltage. The circuit uses a 555 timer IC configured as an astable multi vibrator, i.e., it generates a continuous square wave signal of a set frequency as long as its reset pin (pin 4) is held high. This means that the 555 output toggles between '1' and '0' continuously at the set frequency. This is the figure of the circuit;

When the circuit is powered up and the 555 output (pin 3) goes to logic '1' for the very first time, its near-Vcc voltage level causes C3 to charge up through D2 and also reach near-Vcc level. When the output goes to logic '0', C2 charges from Vcc through D1, also to a near-Vcc level. When the 555 output goes back to logic '1' again, C3 may still have some (if not most) of its charge left, and will allow to charge up to a higher level since it is now effectively in parallel with the series circuit of the 555 level '1' output and the charged C2.

After several cycles of C2 and C3 alternately charging, C3 will subsequently build up a voltage level equal to almost twice the Vcc level. This C3 voltage comes from the charge pumped in by the sum of the C2 voltage (near-Vcc) and the 555 output voltage when it is at logic '1' (also near-Vcc). At this point, the output Vout of the circuit will already be almost twice the Vcc level.

Simple Integrator Circuit

This is a design circuit for simple integrator circuit. The potentiometer is connected to the "rails" of the power source through 100 kΩ resistors, one on each end. This is to limit the span of the potentiometer, so that full movement produces a fairly small range of input voltages for the op-amp to operate on. At one extreme of the potentiometer's motion, a voltage of about 0.5 volt (with respect the ground point in the middle of the series battery string) will be produced at the potentiometer wiper. This is the figure of the circuit;

At the other extreme of motion, a voltage of about -0.5 volt will be produced. When the potentiometer is positioned dead-center, the wiper voltage should measure zero volts. Connect a voltmeter between the op-amp's output terminal and the circuit ground point. Slowly move the potentiometer control while monitoring the output voltage. The output voltage should be changing at a rate established by the potentiometer's deviation from zero (center) position. To use calculus terms, we would say that the output voltage represents the integral (with respect to time) of the input voltage function. That is, the input voltage level establishes the output voltage rate of change over time. This is precisely the opposite of differentiation, where the derivative of a signal or function is its instantaneous rate of change.

If you have two voltmeters, you may readily see this relationship between input voltage and output voltage rate of change by measuring the wiper voltage (between the potentiometer wiper and ground) with one meter and the output voltage (between the op-amp output terminal and ground) with the other. Adjusting the potentiometer to give zero volts should result in the slowest output voltage rate-of-change. Conversely, the more voltage input to this circuit, the faster its output voltage will change, or "ramp."