QwertyTSecond
- Jul 31, 2011
- 6
- Joined
- Jul 31, 2011
- Messages
- 6
I'm currently constructing the coil activation circuit for a coilgun, by using an IR LED and a phototransistor to trigger a relay when the projectile passes through the beam.
This is the circuit I'm using (minus the IR LED + resistor):
In addition, I currently don't have any 100K resistors or pots, so I'm using 10K instead.
I'm finding the coil refuses to work with any external resistance (140 ohms of resistance prevents it from switching when a battery is directly connected).
The relay I'm using is this (RP68Y): http://www.maplin.co.uk/5a-and-10a-miniature-relay-2512
I assume the PN2222's resistance simply doesn't drop by enough, so is it possible to bias it's output in some way or should I look for different relays?
This is the circuit I'm using (minus the IR LED + resistor):
In addition, I currently don't have any 100K resistors or pots, so I'm using 10K instead.
I'm finding the coil refuses to work with any external resistance (140 ohms of resistance prevents it from switching when a battery is directly connected).
The relay I'm using is this (RP68Y): http://www.maplin.co.uk/5a-and-10a-miniature-relay-2512
I assume the PN2222's resistance simply doesn't drop by enough, so is it possible to bias it's output in some way or should I look for different relays?