H7E-P
H7E-P
5
Use a transistor for input that satisfies the following conditions:
Collector breakdown voltage
≥
(Circuit voltage) x 1.2
Leakage current < 5
µ
A
Amplification factor (hFE)
≥
50
Use diode (Di) having a forward voltage as small as possible
(0.1 V max. at I
F
of 20
µ
A).
Operations
PCB counter power source
Wiring polarity must be carefully observed in order to prevent
permanent damage to the counter. The 28-pin socket has no
provision for preventing the insertion of the counter in a
reversed position. Exercise caution when inserting the counter
in the socket, to prevent reversed polarity.
Wiring
Do not route the count, gate or reset input wiring in the vicinity
of, or in parallel to the wiring of high-voltage or inductive load
circuits (such as motors and relays). Also, keep the wiring as
short as possible.
To prevent unwanted reset when replacing the battery, connect
the new battery before disconnecting the old one. Otherwise,
the voltage supplied to the counter circuit drops, causing the
present count value to reset.
When designing the circuit board, providing two extra terminals
for battery connection will make the switch much simpler. See
the schematic diagram below:
■
SOLID-STATE INPUT OF OPEN-COLLECTOR TRANSISTOR
By open-collector transistor
Replacing battery
By TTL or C-MOS IC
