Mutchus

A novel supply voltage monitor which uses a LED to show the status of a power supply. This simple and slightly odd circuit can clearly show the level of the supply voltage (in a larger device): as long as the indicator has good 12 volts at its input, LED1 gives steady, uninterrupted (for the naked eye) yellow light. If the input voltage falls below 11 V, LED1 will start to blink and the blinking will just get slower and slower if the voltage drops further - giving very clear and intuitive representation of the supply's status. The blinking will stop and LED1 will finally go out at a little below 9 volts. On the other hand, if the input voltage rises to 13 V, LED2 will start to glow, getting at almost full power at 14 V. The characteristic voltages can be adjusted primarily by adjusting the values of R1 and R4. The base-emitter diode of T2 basically just stands in for a zener diode. Circuit diagram: Supply Voltage Indicator Circuit Diagram The emitter-collector path of T1 is invers...

This Mini Voltage Source with Adjustable Current Limit variable is very simple and efficient, ideal for small shippers or circuits that require a current limiter with adjustable voltage that this circuit can vary from a few mA up to 2 A and voltage 1.225v up to 12V or more, depending on the power supply.  Once the current reaches the limit set by the 100R resistor, transistor BC547 begins to act on the voltage regulator in the Adj pin and the output voltage starts to decrease. If the output is shorted, the output voltage will reduce to almost zero, as a kind of protection. Adjustable Voltage and Variable Current Limiter Circuit Diagram Adjustable Voltage and Variable Current Limiter Circuit Diagram

This is a Simple Period-To-Voltage Converter Circuit Diagram . The circuit input signal drives ICD. Because ICD`s positive input (V+) is slightly offset to + 0.1 V, its steady state output will be around +13 V. This voltage is sent to ICC through D2, setting ICC`s output to +13 V. Therefore, point D is cut off by Dl, and CI is charged by the current source.  Assuming the initial voltage on CI is zero, the maximum voltage (^Cinax) is given by: When the input goes from low to high, a narrow positive pulse is generated at point A. This pulse becomes -13 V at point B, which cuts off D2. ICC`s V+ voltage becomes zero. The charge on CI will be absorbed by ICC on in a short time.  The time constant of C2 and R5 determines the discharge period— about 10 /is. ICB is a buffer whose gain is equal to (R& + R9)~Rg = lM5. ICD`s average voltage will be (1362f 1.545) + 2 = 1052/. RIO and C3 smooth the sawtooth waveform to a dc output. Simple Period-To-Voltage Converter Circuit Diagram

Description This device is designed to be a simple, inexpensive ‘comparator’, intended for use in a solar cell power supply setup where a quick ‘too low’ or ‘just right’ voltage indicator is needed. The circuit consists only of one 5V regulator, two transistors, two LEDs, five resistors, two capacitors, and one small battery. Although a 4-V battery is indicated, 4.5 V (3 alkalines in series) or 3.6 V (3 NiCd cells in series) will also work. The specifications of voltage regulator IC1 are mainly determined by the size and number of the solar cells and the current pull of the equipment connected to the output. Here the low-drop 4805 is suggested but other regulators may work equally well as long as you observe the output voltage of the solar cells. Transistors T1 and T2 are complementary types i.e. one each of the pnp and npn variety. Circuit diagram: Although the ubiquitous BC557B (pnp) and BC547B (npn) are indicated, any small-signal equivalents out of the junk box will probably do....

Using electronic diagram below can be made a voltage converter that allows laps positive voltage of existing power sources, or convert it into a negative voltage. New supply is electrically isolated from the source through the ferrite transformer wound on a torus G2-3FT12. Primary winding consists of 30 turns. Number of turns in the secondary, n, is calculated using the equation: n = 30 Uo / Ui, where Uo is the desired voltage and Ui is the input voltage. Add to compensate pieriderior 20.05.10 turns. If the output voltage is higher, it can always reduce Pi. Both coil windings can be enamelled copper wire with a diameter of 0.3 mm.  Low Power Variable Voltage Converter Circuit Diagram: The transformer is controlled by a gate CMOS Schmitt trigger and Do with transformed into a rectangular signal generator R1 and C1. Additional current to charge C1 is provided by R2 and Pi, which controls the duty cycle of the rectangular signal. The signal frequency is about 220 kHz and fill factor o...

This is a circuit of Voltage-to-Pulse Duration Converter. This circuit is used to convert voltage into pulse duration by combining a timer IC and an OP Amp. Accuracies to better than 1% can be obtained with this circuit (a), and the output signals (b) still retain the original frequency, independent of the input voltage.  Voltage-to-pulse Duration Converter Circuit Diagram

In this circuit the 555 timer is used in a novel way, as a voltage controlled switch.The old and omnipresent NE555 can be very good at something it was not meant for: driving relays or other loads up to 200 mA. The picture shows an example circuit: if the input level rises over 2/3 of the supply voltage - it will turn on the relay, and the relay will stay on until the level at the input drops below one third of the supply voltage. If the relay and D1 were connected between pin 3 and ground, the relay would be activated when the input voltage drops below one third, and deactivated when the input voltage goes over two thirds of the supply voltage. It is also a nice advantage that the input requires only about 1 uA, which is something bipolar transistors can't compete with. (This high impedance input must not be left open.) A large hysteresis makes the circuit immune to noise. The output (pin 3) can only be either high or low (voltage-wise), and it changes its state almost instantenou...

Description  In this circuit a LM339 quad voltage comparator is used to generate a time delay and control a high current output at low voltage. Approximatey 5 amps of current can be obtained using a couple fresh alkaline D batteries. Three of the comparators are wired in parallel to drive a medium power PNP transistor (2N2905 or similar) which in turn drives a high current NPN transistor (TIP35 or similar). The 4th comparator is used to generate a time delay after the normally closed switch is opened. Two resistors (36K and 62K) are used as a voltage divider which applies about two-thirds of the battery voltage to the (+) comparator input, or about 2 volts. The delay time after the switch is opened will be around one time constant using a 50uF capacitor and 100K variable resistor, or about (50u * 100K) = 5 seconds. The time can be reduced by adjusting the resistor to a lower value or using a smaller capacitor. Longer times can be obtained with a larger resistor or capacitor. To ope...

In many circuits we need to generate an internal adjustable voltage. This circuit shows how it is possible to use a trusty old NE555 timer IC and a bit of external circuitry to create a voltage inverter and doubler. The input voltage to be doubled is fed in at connector K1. To generate the stepped-up output at connector K2 the timer IC drives a two-stage inverting charge pump circuit. The NE555 is configured as an astable multivibrator and produces a rectangular wave at its output, with variable mark-space ratio and variable frequency. This results in timing capacitor C3 (see circuit diagram) being alternately charged and discharged; the voltage at pin 2 (THR) of the NE555 swings between one-third of the supply voltage and two-thirds of the supply voltage. Voltage Inverter Circuit Using IC NE555  The output of the NE555 is connected to two voltage inverters. The first inverter comprises C1, C2, D1 and D2. These components convert the rectangular wave signal into a nega-tive DC leve...

This is very simple Electronic Circuit Project of High voltage supply. A 6 V battery can provide 100-150 Vdc center-tapped at a high internal impedance (not dangerous though it can inflict an unpleasant jolt). A 6.3 V transformer is connected ' 'in reverse'' with a transistor used in a Hartley oscillator configuration. The frequency of operation may be controlled by varying the value of the 10 ohm resistor. Circuit Diagram: The 10 µ¥ capacitor must have a working voltage of at least 250 Vdc.

This is a simple Frequency Voltage Converter Circuit Diagram. Teledyne Semiconductor`s Type TSC9402 is a versatile IC. Not only can it convert voltage into frequency, but also frequency into voltage. It is thus eminently suitable for use in an add-on unit for measuring frequencies with a multimeter. Only a few additional components are required for this.. Just one calibration point sets the center of the measuring range (or of that part of the range that is used most frequently).  The frequency-proportional direct voltage at the output (pin 12—amp out) contains interference pulses at levels up to 0.7 V. If these have an adverse effect on the multimeter, they can be suppressed with the aid of a simple RC network. The output voltage, U0, is calculated by: tfo=C/rei(Ci + 12 pF) R2fm Because the internal capacitance often has a greater value than the 12 pF taken here, the formula does not yield an absolute value. The circuit has a frequency range of dc to 10 kHz. At 10 kHz, the form...

This is the simple frequency voltage converter circuit diagram. Teledyne Semiconductor`s Type TSC9402 is a versatile IC. Not only can it convert voltage into frequency, but also frequency into voltage. It is thus eminently suitable for use in an add-on unit for measuring frequencies with a multimeter.  Only a few additional components are required for this.. Just one calibration point sets the center of the measuring range (or of that part of the range that is used most frequently). The frequency-proportional direct voltage at the output (pin 12—amp out) contains interference pulses at levels up to 0.7 V. If these have an adverse effect on the multimeter, they can be suppressed with the aid of a simple RC network.  The output voltage, U0, is calculated by: tfo=C/rei(Ci + 12 pF) R2fm Because the internal capacitance often has a greater value than the 12 pF taken here, the formula does not yield an absolute value. The circuit has a frequency range of dc to 10 kHz. At 10 kHz, t...

This article is closely related to the article on the excitation system because the working principle of the AVR is to regulate the flow of reinforcement on the exciter. Units operating system AVR (Automatic Voltage Regulator) function to keep the generator voltage remains constant in other words, the generator will remain stab le release tension that always is not affected at the expense of change was alway s chan ging, becau se the load affects the voltage output of the generator. AVR is the working principle of strengthening the curre nt set on t he exciter. If the generator output voltage below the nominal voltage of the generator voltage, the AVR will improve the flow of reinforcement on the exciter. And vice versa if the generator output voltage exceeds the nominal voltage generator AVR will reduce the flow of reinforcement on the exciter. Thus, if the generator output voltage changes can be stabilized by the AVR will automatically due equipped with equipment such as tools used...

A circuit for monitoring supply voltages of ±5 V and ±12 V is readily constructed as shown in the diagram. It is appreciably simpler than the usual monitors that use comparators, and AND gates. The circuit is not intended to indicate the level of the inputs. In normal operation, transistors T1 and T3 must be seen as current sources. The drop across resistors R1 and R2 is 6.3 V (12 –5 –0.7). This means that the current is 6.3mA and this flows through diode D1 when all four voltages are present. However, if for instance, the –5 V line fails, transistor T3 remains on but the base-emitter junction of T2 is no longer biased, so that this transistor is cut off. When this happens, there is no current through D which then goes out. Streampowers

The LM3914 is a truly versatile component. Besides LEDs, only a few other components are needed to make the ‘bidirectional’ bargraph voltmeter shown here. The circuit is similar to a conventional bar display, but it offers a possibility to change the direction in which the LEDs are switched on. This may be useful, for example, when positive and negative voltages are measured. For a positive input voltage, the LEDs are switched on in the usual manner, that is, from D3 to D12, while for negative voltages, the LEDs are switched on in the opposite direction, from D12 to D3. Obviously, the negative voltage must be ‘rectified’, i.e. inverted, before the measurement. A suitable circuit for this purpose is presented in the article ‘Absolute-value meter with polarity detector’ elsewhere in this website. A set of transistor switches (MOSFETs) controls the direction in which the LEDs light. When the control voltage is high (+6V, according to the schematics, but any voltage that is at least 3V hig...

This is a Simple Voltage to Current Converter Circuit Diagram. This is an electronic circuit, The current out is Iqut—Vin/R. For negative currents, a PNP can be used and, for better accuracy,-a Darlington pair can be substituted for the transistor. With careful design, this circuit can be used to control currents of many amps Unity gain compensation is necessary. Simple Voltage to Current Converter Circuit Diagram  

Here this circuit diagram is for +12V regulated (fixed voltage) DC power supply . These power supply circuit diagram is ideal for an average current requirement of  1Amp. This  circuit is based on IC LM7812 . It is a 3-terminal (+ve) voltage regulator IC. It has short circuit  protection , thermal overload protection.  LM7812 IC is from LM78XX series. The LM78XX series IC is  positive voltage regulator IC for different voltage requirements, for example LM7805 IC is made for 5 volt fixed output voltage . There is LM79XX IC series for negative voltage . Circuit diagram of 12V fixed voltage power supply   A transformer(Tx=Primary 230 Volt, Secondary 12 Volt , 1Amp step down transformer) is used to covert 230V to 12V from mains. Here used a bridge rectifier made by four  1N4007 or 1N4003 diode to convert AC to DC . The filtering capacitor 1000uF,25V is used to reduce the ripple and  get a smooth DC voltage. This circuit is very easy to build. For goo...

People often forget that many voltage regulator ICs have an upper limit (usually 35 V) on the input voltage they can handle. That applies primarily to types with a fixed output voltage. Adjustable voltage regulators also have a maximum voltage specification, in that case between the input and output (commonly 40 V). The input voltage must thus be limited to that level in a fault situation in which the output is shorted. This circuit shows a way to allow such regulators to be used in situations with higher input voltages. Although the solution consists of an additional three components, it is simple and can be built using commonly available components. Voltage Regulators Protector Circuit Diagram The voltage across the regulator is limited by the combination of T1 and zener diode D1 to a value that allows the regulator to work properly with loads up to the maximum rated load. R1 provides an adequate operating current for D1 and the bias current for T1. It’s a good idea to use a Darlingt...

This high voltage generator was designed  with the aim of testing the electrical break-down protection used on the railways. These  protection measures are used to ensure that  any external metal parts will never be at a  high voltage. If that were about to happen,  a very large current would flow (in the order  of kilo-amps), which causes the protection  to operate, creating a short circuit to ground effectively earthing the metal parts. This hap-pens when, for example, a lightning strike hits  the overhead line (or their supports) on the  railways.  This generator generates a high voltage of  1,000 V, but with an output current that is limited to few milliamps. This permits the electrical breakdown protection to be tested with-out it going into a short circuit state. The circuit uses common parts throughout: a  TL494 pulse-width modulator, several FETs or  bipolar switching transistors, a simple 1.4 VA  mains tran...

This Voltage Regulator with Shutdown Digital Circuit Diagram is very interesting, it uses an LM317 regulator circuit that allows external control in a dangerous situation to turn off the regulator output in response to the trigger. The circuit is configured to output five volts suitable for all TTL logic circuits. The selected values ​​of R1 and R2 set the output to the required 5V, R2 can be changed to other values ​​other output voltages. In unfavorable external trigger switches the transistor instantly putting R2 shorted to ground, knocking the output to zero volts.As the circuit is equipped with the function off by an external trigger, it is extremely suitable for many critical applications and for use in Arduino projects. Voltage Regulator with Shutdown Digital Circuit Diagram