This battery charger circuit is used to recharge the rechargable lithium battery. The circuit comes from Molicel. Charging is accomplished with a constant current of 60 mA for AA cells to a cutoff of 2.4V per cell, at which point the charge must be terminated.
Here is the AM Radio receiver circuit diagram based on old single IC MK484. Components List: R9, R10_________ 6R8 R6_____________ 100R R3_____________ 1K R1_____________ 4K7 R7_____________ 5K6 R4_____________ 10K R2_____________ 100K R5_____________ 150K R8_____________ 820K Pot_____________ 10K log pot Coil & ferrite bar set C7______________ 470p ceramic C, C4, C5, C6_____ 470nF monoblock C2______________ 100nF… Read More »
This is 25W low power inverter which contain of only 9 parts and turn 10VDC – 16VDC into 115V / 60Hz square wave power. This circuit has capability to operate AC equipment up to 25W. The first section of the 555 timer is wires as an astable oscillator with R2 and C1 setting the frequency.… Read More »
This is an adjustable / variable power supply which have adjustabled output voltage from 6-12 DC volt. This power supply can be used for general circuit or gadget which require 6 – 12DC voltage to work. Component Parts List: T1 = primary 115[220]/secondary 8 VAC transformer. Center Tap not needed. Q1 = 2N1613, NTE128, or… Read More »
This is the basic dark and light sensor which using photoresistor as sensing component. The transistor act like as a switch, when the “switch” in on condition then the relay will be activated.
This circuit is a powerful three stage, 9V FM transmitter (Tx) with a range of up to 1 kilometer in the open. It uses an RF transistor in its output stage and two BC547″s for the first two stages. Distance of trans-mission is critically dependent on the operating Conditions (in a building or out on… Read More »
Here is the wailing alarm siren circuit diagram: Components List: R1,R5___________ 4.7K R2______________ 47K R3______________ 10K R4______________ 100K Rx______________ *see text C1,C4__________ 100uF/25V, electrolytic C2,C3__________ 0.01uF (10nF), ceramic T1_____________ 2N3702 (NTE159, TUP, etc.) IC1,IC2________ LM/NE555, MC1455P, etc LS_____________ Loudspeaker
This is a 12VDC to 9VDC converter circuit. You may use this DC to DC stepdown converter circuit if you have fixed 12V power supply / battery, but you need 9V power supply for your electronic devices. Scheme Diagram: Components List: R1________ 560 ohm, resistor C1________ 1000uF/16V, Electrolytic capacitor C2________ 100uF/16V, Electrolytic capacitor C3________ 330nF,… Read More »
If you’re interested in RF circuit, then you should know about this basic RF oscillator. This basic RF oscillator circuit is easy to build and the components are not critical. Most of them can be found in your junk parts box. The circuit operated with 9VDC power supply. The L1 antenna col can be made… Read More »