Schematic Diagram: indicator

Wednesday, November 19, 2014

3 Level Audio Power Indicator

This circuit is designed to indicate the power level output of any audio amplifier. Its simple, portable, and displays three power levels can be adjusted to any desired value. For a standard power amplifier hi-fi stereo, the output values suggested are:

D5 illuminates at 2W
D4 illuminates at 12.5W
D3 illuminates at 24.5W

The above values were selected for easy setup, but other options are possible. IC1A is the input buffer, feeding 3 voltage comparators and LEDs drivers by means of a variable DC voltage obtained by R5 and C4 smoothing action. In order to achieve stability of adjustment, the supply of IC1 and trimmers R6 and R7 is reduced and is subject to 5.1V by Zener diode D1.

Very Simple Peak Indicator Circuit

This series is made to indicate that the amplifier has been given the maximum signal, the amplifier has the ability to be at its peak. if the lights do not mean the signal-plus volume.the way it works is the LED lights will light up when given a signal that more than 1.8 volts, the average amplifier will be saturated (maximum) if the signal was given more than this.

The circuit is very simple to the point that we forget that making a series of peak signal can in this way. circuit is mounted on the output tone control IC, master mixer output, or input power amplifier. This series does not impose on other circuits.survived the experiment!

Thursday, October 30, 2014

Modem Off Indicator Circuit Diagram

The modem off indicator is intended especially for serious Internet surfers. It will be seen that the circuit of the indicator cannot be much simpler, or there might be nothing left. In spite of its simplicity, it may prove to be a cost-saving device, since it shows at a glance whether the telephone line is free again after the modem has been used. This obviates high telephone charges in case for some reason the modem continues to operate. The circuit depends on the fact that there is a potential of about 40 V on the telephone line when it is not busy. This voltage drops sharply when a telephone call is being made. If, therefore, the circuit is linked to telephone terminals a and b, the lighting of the green LED shows that the line is not busy in error.

Modem Off Indicator Circuit diagram:

Modem Off Indicator Circuit Diagram

The bridge rectifier ensures that the polarity of the line voltage is of no consequence. This has the additional benefit that polarity protection for the LED is not necessary. To make sure that the telephone line is not loaded unnecessarily, the LED is a high efficiency type. This type lights at a current as low as 2 mA, and this is, therefore the current arranged through it by resistor R1.

WARNING.

In spite of the liberal age we live in, it is highly probable that in many countries it is not allowed to connect the indicator across the telephone lines. Seek advice of your local telephone company that owns or operates the telephone network.

Thursday, September 25, 2014

IC 723 Power Supply Circuit with Current Indicator

This can be . increased readily by fitting a resistor in parallel with Ra, until the output voltage is5.0 V precisely Switches S1 and Sz are preferably SPDT types with a centre position, but three-way rotary switches should also do if in both cases the centre contact is not used.
A difficulty arises if it is intended to provide an overcurrent indication for the shutdown circuit with the aid of an external transistor fitted in parallel onto pins 2 and 3, since the external and internal transistor are highly unlikely to have precisely the same characteristics.
A further transistor, T3, has been added to keep the base current for T2 as low as possible.
The output voltages of the supply may not be as accurate as required, and this is mainly due to the use of resistors from the E12 series. Close tolerance is especially important in the 5 V range, since the value shown for R3 gives a theoretical output of 4.9 V
The three output voltages from this supply are probably the , most commonly used for testing asymmetrically fed designs: 5 volt for many TTL and CMOS circuits, 9 volt for battery operated equipment or logic circuits equipped with a 7805 regulator (this requires, an input of at least 8.5 V), and 12 volt for RS232 drivers, and miscellaneous opamp or tran- sistor based circuits.
Since the base-emitter junction then has a diode characteristic, the associated voltage drop is always lower than that of the transistor internal to the 723.
The current limiter can be set to l0 mA, 100 mA, or l A for safely power- ing- experimental circuits. Power regulator T1 should be fitted with a heat sink sized at least l0 ><‘10 cm. leds dv (green) and ds (red) are the power on and current overload indicator, respectively.
When the internal transistor has the low B—E voltage of the two, the indication will not work, while in the other case the external transistor takes away the base current for the internal transistor, so that the current limiter is rendered ineffective. In this design of a power supply, a current overload indication was realized by fitting the external transistor with a high value base resistor, Rv, to ensure that the current limiter in the 723 is not disabled.

Monday, September 8, 2014

Battery Voltage Indicator Circuit

Connecting this schema to the battery of your vehicle, you will always know at a glance the approximate voltage available. An indication of battery voltage is useful to the motorist for monitoring the batterys capacity to deliver current, and as a check on the efficiency of the dynamo or alternator. Threshold voltages of the Leds are set by means of two Zener Diodes (D6 & D10) plus two further Diodes wired in series (D4, D5 and D8, D9 respectively) adding a step of about 1.3V to the nominal Zener voltage.

Parts:

R1 = 1k
R2 = 100K
R3 = 1k
R4 = 3.3K
R5 = 3.3K
R6 = 1k
R7 = 3.3K
R8 = 3.3K
Q1 = BC547
Q2 = BC547
Q3 = BC557
D1 = Red Led
D2 = Amber Led
D3 = 1N4148
D4 = 1N4148
D5 = 1N4148
D6 = BZX79C10
D7 = Green Led
D8 = 1N4148
D9 = 1N4148
D10 = BZX79C12

Notes:

* Red LED D1 is on when battery voltage is 11.5V or less. This indicates a low battery charge. * Amber LED D2 is on when battery voltage is comprised in the 11.5 - 13.5V range. This indicates that the battery is good if the motor is off. When motor is running, this indicates no charge from dynamo or alternator. * Green LED D7 is on when battery voltage is 13.5V or more. This indicates a normal condition when motor is running and dynamo or alternator is charging.

Saturday, September 6, 2014

LM3914 battery level indicator

Battery level indicator circuit is a circuit that is used to measure the battery voltage / battery. The main components of the battery level indicator circuit is an LM3914 IC. LM 3914 on Circuit battery level indicator is a monolithic IC that detects an analog voltage. And drive the 10 LEDs that produce a linear analog display on a given input voltage.

Sunday, August 17, 2014

Temperature Indicator circuit diagram

This t sink in high power diagram. In this temperature indicator, diode voltage drop in ambient temperature is used as reference level. Temperature is measured by a transistor mounted on a radiator or near power transistor controlled.T1 temperature sensor and voltage to the base - emitter is compared, through potentiometer P1, with the common point of reference in its D1 and R1.

Temperature Indicator schema diagram

Transistor remains blocked as long as temperature remains below a certain level, which is set to P1. Base-emitter voltage of transistor will decrease by about 2mV for a temperature increase of about 1 ° C. When the emitter voltage of transistor voltage falls below the cursor P1, the transistor will go into conduction and D2 will light.The values of R1 and R2 are voltage dependence of Ub and relationships can be calculated:
R1 = [(Ub - 0.6) / 5] k, R2 = [(Ub - 1.5) / 15] k