Automatic simple 12V 100mA NiCd Battery Charger circuit

Today we are going to learn how to make a very cheap NiCd battery charger with overvoltage protection or control circuit. This circuit is very much simple and specifically designed for 12V NiCd battery. The charger have current and voltage control at the same time.

Its charging current is around 100mA but we can change it using the formula : (Vd1 - 0.7) / R2 ; where Vd1 is voltage of zener diode D1.

Its Cutoff voltage is limited to Vd2 - 0.7 ; where Vd2 is voltage of zener diode D2

Part List:-

R1 - 2.7 kilo ohms 1/4watt

R2 - 56 ohms 1Watt

D1 - 1N4735A or any 6.2V zener diode

D2 - 1N5244B or any 6.2V zener diode

D3 - 1N4001 or similar diode

Q1 - 9013, 2N2222 or similar NPN transistor

Q2 - 2N3440 or similar NPN transistor

Simply solder the above circuit and enjoy simple 12v 100 mA or change it.

For any further querry please ask them in comment section. I wil be happy to help.

Make a simple electronic audio amplifier using LM317

Today we are going to learn how to make a simple amplifyer which can amplify any audio signal by using LM317 regulator IC. The amplifier can deliver upto 1W power max and needs only few parts which are easily available. This circuit is originally from vegmatic1966 youtube channel.

Part List:
C1, C3 - 10uF electrolytic capacitor rated 16V

C2 - 470uF electrolytic capacitor rated 16V

R1 - 470 ohms 1/2W

R2 - 10 ohms 2W

POT1 - 5 kilo-ohms potentiometer

SPK - 8 ohms rated 1W speaker

LM317 - 317 or any similar regulator IC

What to do:-

After you assembled the circuit shown above, adjust potentiometer POT1 until the voltage across R2 terminals is half the supply voltage (around 4.5V approximately).

Don't forget adding heatsink or any aluminium sheat for cooling the IC LM317 because it will going to heat up a lot. Check the polarities and pins of the parts before testing.

Part pinouts: