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This is the Simple Transmission Indicator Circuit Diagram. This circuit the push-to-talk button is closed the light will go on. The antenna samples the output RF from the transmitter. That signal is then rectified (detected) by germanium diode Dl, and used to charge capacitor C2. Simple Transmission Indicator Circuit Diagram The dc output is used to trigger a small silicon-controlled rectifier (SCR1), which permits the current to flow through the small pilot lamp. For lower-power applications, such as CB radio, the antenna will have to be close-coupled to the antenna.

This simple programmer will accept any device that's supported by software (eg, IC-Prog 1.05 by Bonny Gijzen at www.ic-prog.com). The circuit is based in part on the ISP header described in the SILICON CHIP "PIC Testbed" project but also features an external programming voltage supply for laptops and for other situations where the voltage present on the RS232 port is insufficient. This is done using 3-terminal regulators REG1 & REG2. The PIC to be programmed can be mounted on a protoboard. This makes complex socket wiring to support multiple devices unnecessary. 16F84A, 12C509, 16C765 and other devices have all been used successfully with this device. Circuit diagram: Simple Universal PIC Programmer Circuit Diagram Author: Luke Weston Copyright: Silicon Chip

SIMPLE DOOR ALARM CIRCUIT Here is the circuit diagram for simple door bell, you can assemble this circuit inside your room or home where as keep the switch outside your home or room that is easily noticable by the visitors. The working of this circuit is almost similar to my previous project. Simple Melody Maker Circuit Figure shows the circuit diagram of Simple door alarm.

This is very very simple circuit audio amplifier  based on IC7057T  , you just use 3 components you can make this circuit . And the minimum voltage is 1 Volts , with just 1 Volt  you can operate this amplifier. Maximum voltage 6,5 volts . Maximum Power output 35mW with 32 ohms impedance. See circuit below : Very simple stereo amplifier

This a simple 15v variable power supply circuit is using 2N3055 transistors. Output voltage of this variable power supply can be adjusted in the range between 1.5 and 15 volts. 15V Variable Power Supply Circuit Diagram: This 2N3055 15v variable power supply can provide a maximum current of 500 mA. Stabilization is better than 2%, if the currents do not exceed 350 mA. Voltage is set using a potentiometer, and the presence of overload is announced by an audible indication of overload. T4 transistor compare the voltage at the cursor P1 with the output. When this voltage is higher with 0.65 V than regulated voltage, T2 opens, leading to suppression of the current Darlington power stage, T3-T5. In this mode, the output voltage of the source is higher than 0.65 V reference voltage on the base of T4, which comes from a 15 V zener diode.

After the success of small modules USB – I / O converters – PUSBIO with MCP2200 circuit intended for development and small batch production, which we introduced in Article MCP2200 USB module and I / O , and recently introduced software for USB I / O modules , now the company introduces new modules Pandatron with relays and optocouplers.

This is a water sensor /rain alarm circuit diagram; it can be used on motorcycle, car or other device that we want to protect from water, rain. This is a simple water sensor/rain alarm circuit that makes an alarm when water/rain falls on its sensor. This circuit is based on NE555/LM555 IC and two transistors (Q1&Q2). For transistor Q1- BC547 or BC107 and for Q2- 2N825,BC548 or BC168 can be used in the circuit.  This rain detector circuit can be supplied from voltage source of +9V-12V DC. The resistor 470K ohm is a POT/Variable resistor; it is used to adjust the sensitivity of water/rain sensor. Use a 8 ohm,0.5w-1W speaker to hearing better alarm. Less than 8 ohm speaker could be harmful for the IC 555.  Circuit Diagram of Water Sensor   We can make the water sensor as shown in the image (Fig-1) using aluminu m conductor like a naked wire . Here can be used other conductor but we suggesting to use aluminum.

Power-up/down Sequencer Circuit Diagram. Whether you’re talking about a home cinema  or a computer system, it’s very often the case  that the various elements of the system have  to be turned on or off in a quite specific order,  or at least, automatically. Constructing this  sort of automation system is well within the  capability of any electronics enthusiast worthy of the name, but in this ‘all-digital’ age,  most of the circuits of this type to be found  in amateur electronics magazines or web-sites use a microcontroller. Even though that  is indeed a logical solution (in  more ways than one!), and you  might even say the easiest one, it  does pose problems for all those  people who don’t (yet) have the  facilities for programming these  types  of  IC.  So  we  decided  to  offer you now an approach that’s  very different, as it only uses a  simple, cheap, commonly...

This is a light switch or light activated relay circuit .The relay on when LDR uncoverd and relay off when LDR covered .Adjust VR1 for light sensitive.LED will turn on at the same time with relay

This Photodiode based Alarm can be used to give a warning alarm when someone passes through a protected area. The circuit is kept standby through a laser beam or IR beam focused on to the Photodiode. When the beam path breaks, alarm will be triggered.   Photodiode Alarm Circuit Diagram   The circuit uses a PN Photodiode in the reverse bias mode to detect light intensity. In the presence of Laser / IR rays, the Photodiode conducts and provides base bias to T1. The NPN transistor T1 conducts and takes the reset pin 4 of IC1 to ground potential. IC1 is wired as an Astable oscillator using the components R3, VR1 and C3. The Astable operates only when its resent pin becomes high. When the Laser / IR beam breaks, current thorough the Photodiode ceases and T1 turns off. The collector voltage of T1 then goes high and enables IC1. The output pulses from IC1 drives the speaker and alarm tone will be generated. IR Transmitter Circuit   A simple IR transmitter circuit is given w...

This is the Simple Homemade Melody Door Bell Circuit Diagram. In most of the homes the door bells are conventional ding-dong type. Most of us don’t like its sound. Due to mechanical moving parts with spring mechanism its long term durability is questionable. I had also one such door bell in my home. After a period of time its performance deteriorates and one time it becomes completely intolerable because of its noisy irritating sound. The new types of door bells available in market are bird sound door bell. They are costly. and even I didn’t like it because of its high frequency and high volume sound output.     Simple Homemade Melody Door Bell Circuit Diagram   So the idea came into my mind that why not to build a very simple door bell with few components that gives nice melodious output and that is at the less cost also. So I build this door bell with all the items available in home. Let us see how I have made it. Description First collect the required compone...

This circuit will provide an indication whenever the input voltage differs from two defined limits, V1 and V2. The limits are adjustable and the circuit made to trigger from the adjustable "window". Circuit Diagram: Notes: This circuit will provide an indication whenever the input voltage differs from two defined limits, V1 and V2. The supply voltage, Vcc must be higher than the highest input voltage by at least 2 volts. One application here is to monitor a 12V car battery. V1 could be set to 14V and V2 to 11V thus giving an indication of over charge or a weak battery. Please Note. Only pins 7 and 4 (power supply), pin 6 (output) and pins 2 and 3 (inverting and non-inverting inputs) are used. All other pins are not connected. The pinout for the CA3140 is shown below. The op-amps used here are MOSFET CA3140. They are used to advantage as they have very little output offset voltage and can switch down to near 0 volts. If any other op-amp is used such as LF351 or CA741 then it w...

Here is the simplest melody generator circuit you can make using an IC.The UM66 series are CMOS IC’s designed for using in calling bell, phone and toys. It has a built in ROM programmed for playing music. The device has very low power consumption.Thanks for the CMOS technology.The melody will be available at pin3 of UM66 and here it is amplified by using Q1 to drive the speaker.Resistor R1 limits the base current of Q1 within the safe values.Capacitor C1 is meant for noise suppression. Parts: R1 = 4.7K IC = UM66T Q1 = 2N2222 C1 = 10uF-16v S1 = On/Off Switch B1 = 1.5 - 4.5 Battery SP = 2R Speaker Notes: Power supply must be between 1.5V & 4.5V .Do not exceed 4.5 V. Speaker can be driven with external NPN transistor. Melody begins from the first note if power is reseted. Assemble the circuit on a good quality common board.

This simple Simple Mat Switch Circuit Diagram produces a warning beep when somebody crosses a protected area in your home or office. The switch, hidden be-low the floor mat, triggers the alarm when the person walks over it. The circuit uses a conductive foam as the switch. It can be two small pieces of conductive pads usually used to pack sensitive ICs as antistatic cover. Alternatively, you can make the switch by coating conducting carbon ink on two small pieces of a copper-clad board. Circuit diagram : Simple Mat Switch Circuit Diagram When the circuit is in standby mode, transistor T1 does not conduct, since its base is floating. When the person walks, the switch is pressed and current flows through R1 and the switch to provide positive bias to transistor T1. Transistor T1 conducts and its collector voltage drops, which acts as a negative trigger input for the monostable wired around IC NE555 (IC1). IC1 outputs a pulse of fifty-seconds duration with preset values of R4 and C3. This...

There are components that have special characteristics , one of them is the 1N4148 diode , it is a diode High - speed , and its switching speed is 4th , its voltage is 100 V and current of 450 mA . It besides a diode 1N4148 is used as the temperature sensor , that due to its characteristics that cause it to change its resistance with temperature change . Of course it does not compare to a sensor like the LM38 , but for some circuits of low precision , which just need to know if an element is hot or cold it is very useful .   Temperature Sensor Circuit using 1N4148 diode Diagram Using the multimeter and the 1N4148 as a thermometer The scheme above is a circuit that measures the temperature in a simple manner using a multimeter. It uses 1N4148 diode , and VR1 and VR2 must be adjusted with a thermometer , and is more precise measurement . On the scale of the multimeter can be compared to the scale of degree...

How to Build Simple 3000 Watts UPS Circuit Diagram. This is a Simple 3000 Watts UPS Circuit Diagram Simple 3000 Watts UPS Circuit Diagram

This is the Simple 250W Inverter Circuit Diagram.In this time a 555 timer (IC1) generates a 120-Hz signal that is fed to a CD4013BE flip-flop (ICl-a), which divides the input frequency by two to generate a 60-Hz clocking frequency for the FET array (Ql through Q6).Transformer Tl is a 12-/24-V center-tapped 60-Hz transformer of suitable size.  Simple 250W Inverter Circuit Diagram  Sourced by: www.circuitsstream.com

The circuit is intended for carrying out harmless experiments with high-voltage pulses and functions in a similar way as an electrified fence generator. The p.r.f. (pulse repetition frequency) is determined by the time constant of network R1-C3 in the feedback loop of op amp IC1a: with values as specified, it is about 0.5 Hz. The stage following the op amp, IC1b, converts the rectangular signal into narrow pulses. Differentiating network R2-C4, in conjunction with the switching threshold of the Schmitt trigger inputs of IC1b, determines the pulse period, which here is about 1.5 ms. The output of IC1b is linked directly to the gate of thyristor THR1, so that this device is triggered by the pulses. The requisite high voltage is generated with the aid of a small mains transformer, whose secondary winding is here used as the primary. This winding, in conjunction with C2, forms a resonant circuit. Capacitor C3 is charged to the supply voltage (12 V) via R3.When a pulse output by IC1b trigge...

This is the simple Reset Protection For Computers Circuit Diagram. This protection circuit is inserted between the reset switch and the motherboard. The earth connection of the computer must be linked to terminal of the protection circuit. The protection circuit can draw its power from the computer supply. When the circuit has been fitted, operation of the reset switch will not immediately restart the computer. Instead, a buzzer will sound to alert you to the reset operation.    Simple Reset Protection For Computers Circuit Diagram The buzzer is actuated for 4 s by monostable IC1A, which is triggered by the reset switch. During these 4 s, the output, pin 5, of IC1A ensures that the reset function, pin 10, of IC1B is disabled. When the reset switch is operated again, monostable IC IB will be triggered and this starts the reset procedure. Transistor T2 is then switched on for 0.5 s and the buzzer is deactuated via Rll and D4. The circuit around T1 and N4 ensures that IC1A can ac...

This is the Simple Car Alarm Arming Horn Beep Canceller Circuit Diagram Project. It's a great convenience that most modern cars come with a built in alarm, however it is nothing but noise pollution that the horn sounds when the alarm is armed. Disconnecting the alarm system from the horn relay will eliminate this, but prevent the horn from sounding in the even of an actual alarm. This circuit serves to silence the arming beep yet maintain the alarm by introducing a small delay into the signal.    Car Alarm Arming Horn Beep Canceller Circuit Diagram       It sits between the alarm and horn relay. The alarm must provide a constant horn signal for at least 3 seconds before the horn relay is activated. That way the quick "beep" will never activate the horn relay, while the constant alarm signal will. Part           Total Qty.             Description C1 ...